Emalus Library Online Documents
Collection - Customary Law
AN APPROACH TO CUSTOMARY LAW
Alan Watson *
Source: University of Illinois Law Review ,1984; 1984 U. Ill. L. Rev. 561
* Nicholas F. Gallichio Professor of Law, University of Pennsylvania; M.A., LL.B.,
University of Glasgow; B.A., B.C.L., M.A., D. Phil., D.C.L., University of Oxford; LL.D.,
University of Edinburgh. I wish to dedicate this paper to the Molt Illustre Govern de les
Valls d'Andorra and to Antoni Morell, Secretari d'Estat. I am grateful to my friends
Stephen B. Burbank, Michael H. Hoeflich, Neil MacCormick, and Ann E. Mayer who read a
draft of this paper and gave much helpful criticism. An invitation to deliver a lecture
in, Andorra gave me a much-valued opportunity to deepen my understanding of customary law.
... A proper understanding of the nature of customary law is important for legal
historians. For students of European legal history, customary law is particularly
important; from post-Roman times to the beginning of the modern legal age in the
eighteenth century, the two main elements in European law have been Roman law and legal
custom. ... Accepting this reasoning makes it logically impossible, under the current
doctrine of opinio necessitatis and custom, for customary behavior to create law.
... Thus, if opinio necessitatis is at the root of customary law, the doctrine
does not allow the desuetude of a customary legal rule when that legal rule is remembered.
... Savigny, despite his powerful argument that opinio necessitatis does not fit
within the framework which historians usually attribute to customary law, retains the
notion. ... The basis of local customary law is frequently treated as custom rather than
judicial precedent even though acceptance of the rule actually stems from local judgments
rather than from antecedent local behavior. ... To become law, custom, like legislation
and binding precedent, must be clothed with the requisite form which marks its official
acceptance by the sovereign. ...
A proper understanding of the nature of customary law is important for legal historians.
For students of European legal history, customary law is particularly important; from
post-Roman times to the beginning of the modern legal age in the eighteenth century, the
two main elements in European law have been Roman law and legal custom. In large measure,
the main task of lawyers of that interim time period was to unify or harmonize the two
strands of Roman law and custom.
Customary law flourishes in circumstances where law is likely to be the least theoretical.
Yet, the nature of any
source of law requires theoretical underpinnings regardless of whether these underpinnings
are always implicit and never expressed. Accordingly, for custom to be regarded as law in
Western private law, more than simple usage must be and is required, even if the usage is
general and has long flourished. The principal issue is that one cannot derive an ought
from an is. Consistent behavior in accordance with particular implicit rules does
not indicate that people should so behave, or conversely should be subject to some
sanction if they do not.
The main problem for any theory of customary law seems to be determining the nature of the
additional factor required to transform custom into law. The Roman sources clearly
indicate that some additional factor is needed to recognize custom as law, even if the
nature of this factor is not apparent. For example, the Epitome Ulpiani states
that [*562] "[c]ustom is
the tacit consent of the people, deeply rooted through long usage." The additional factor is
expressed by the otherwise tautological "tacit consent" or "tacit
agreement" (tacitus consensus). But, this approach raises the question as to
what has tacit consent been given? Certainly, tacit consent is not given to the
long usage itself, although the tacit consent is rooted in the long usage. Another Roman
source, the Justiniani Institutiones, states that "[u]nwritten law is that
which usage has approved. For long-practiced customs, endorsed by the consent of the
users, take on the appearance of statute."
In this instance, the additional factor is expressed by "endorsed by the consent of
the users" (consensu utentium comprobati).
Nevertheless, the vagueness of Ulpian is not dissipated as a result of this other
explanation. The Justiniani Digesta, however, clarifies the nature of the
additional factor by stating that
[d]eeply rooted custom is observed as a statute, not undeservedly; and this is what is
called law established by usage. For since statues themselves bind us for no other reason
than because they have been accepted by the judgment of the people, then deservedly those
things which the people have approved without writing will bind all. For what does it
matter that the people declare its wish by vote or by positive acts and conduct?
Therefore, it is very rightly accepted that laws are abrogated not only by the vote of him
who proposes law, but also through desuetude, by the tacit consent of all.
For Julian, the nature of the additional factor seems to be clearer: apparently the custom
is law because the people accept it as law.
This article discusses the dominant theory which legal historians have adopted to explain
how custom is transformed into law: opinio necessitatis. Although legal
historians generally accept the doctrine, it has a number of theoretical failings which
hamper its usefulness as an explanatory tool. Accordingly, this article analyzes those
failings and an alternate theory that custom becomes law only when it is the subject of
statute or judicial decision. Finally, the article proposes nine propositions related to
the role of judgments in creating customary law.
II. OPINIO NECESSITATIS
For a long time after Justinian, scholars made little progress in defining the nature of
the additional factor. Eventually, the idea of
opinio necessitatis, which by implication may have its roots in Julian's
text, appeared and, despite some
opposition, still appears to be the dominant theoretical explanation. The thrust of opinio
necessitatis is that individuals purposely follow a certain rule simply because they
believe it to be a rule of law. Modern theorists like Larenz have explained the concept in
One can say the practice must be the expression of an "intention of legal
validity" of the community or of a "general conviction of law," provided
only that one is clear that this "intention of legal validity" or the
"general conviction of law" is not solely a "psychological fact"
but the "sense of fulfilling a norm" (of a legally commanded behavior)
developing or dwelling in the individual acts of conduct according to the judgement of
those sharing the same law.
Under this view, custom becomes law when it is known to be law, is accepted as law, and is
practiced as law by persons who share the same legal system. But suppose that once the
custom is known to be law and is accepted as law, the practice changes. Does the old law
cease to be law, and the new practice become law? If this does happen, at what moment does
it happen? And, what is the machinery for change?
In analyzing these questions, the legal historian will note two different responses to the
change in custom. In the first situation, those subject to the law remember the past
custom. In the second, they forget the past custom. In the first situation, which is of
greater importance both in theory and in practice, a contrary practice cannot change the
law. So long as people remember the past custom as being law, there can be no point on the
custom-law continuum at which the new practice usurps what in consciousness has been the
law. Accordingly, the outmoded practice must cease to be law before a different law can
begin to emerge from customary usage. Unfortunately, the theory of opinio necessitatis
contains no mechanism for deleting law that no longer commands approval.
Opinio necessitatis contains a number of theoretical flaws which limit its
usefulness in explaining the transition from custom to law. A principal failing is that opinio
necessitatis provides no mechanism to incorporate changing customs or to delete law
which ceases to mirror [*564] common practice.
One might try to resolve this inadequacy by postulating that the doctrine of desuetude is
inherent in customary law. The doctrine of desuetude states that when a practice that is
recognized as law ceases to be followed or to be regarded as law, it ceases to be law. At
that stage, but not before, the road becomes clear for the creation of new customary law.
Adherence to the new custom before the old customary legal rule becomes obsolete is a
factor in making the old legal rule obsolete. However, under the doctrine of opinio
necessitatis, overlapping practice does not create a new legal rule because the new
practice was not followed in "the general conviction of law." Thus, at the precise
moment of desuetude, there is no law on the point at all.
Against this proposed resolution, however, stands Savigny's objection to opinio
necessitatis. Savigny points out that within the framework that legal historians
usually attribute to custom, custom should not rest
on error. Roman sources expressly make the same point.
According to Savigny, this principle nevertheless leads to a contradiction without
solution. Under Savigny's reasoning, a rule of law should arise first through custom; but,
at the time of the first behavior the law was, of course, not in existence. In order to
create law through conformity to custom, however,opinio necessitatis should
accompany this first relevant behavior. Consequently, the first behavior rested on an
error because the behavior was not accompanied by opinio necessitatis and should
not be counted towards the creation of the customary law. This analytic approach also
applies to the second act of behavior, which then replaces and becomes the first, and so
on for all subsequent acts.
Accepting this reasoning makes it logically impossible, under the current doctrine of opinio
necessitatis and custom, for customary behavior to create law. A fortiori,
when the new customary behavior was being adopted, a different rule of customary law
already existed; therefore, any belief that the new behavior conformed to existing law was
clearly erroneous. If custom cannot create a legal rule, custom certainly cannot both
create and substitute a new legal rule for the established rule which custom abolished.
Thus, if opinio necessitatis is at the root of customary law, the doctrine does
not allow the desuetude of a customary legal rule when that legal rule is remembered.
Customary law is a "general conviction of law"; hence, it corresponds to what
people generally do. People conform to customary law because it is the law. Failure to
conform would be an unacceptable deviant act contrary to law." The point is not that
customary behavior does not change; rather, under the doctrine of [*565] opinio
necessitatis, when a rule of customary law exists and is remembered, the rule cannot
become obsolete by desuetude. In other words, acts which are known to be contrary to the
rule cannot affect the rule's efficacy.
The doctrine of opinio necessitatis presents a further and more important logical
difficulty in accepting the doctrine of desuetude of customary law. A legal rule can only
fall into desuetude if another legal rule replaces the existing rule regardless of whether
this later rule merely states that the first rule no longer applies. But under a theory of
opinio necessitatis, the new rule can only come into existence after the old
known rule is recognized as extinct. Otherwise, those subject to the law would not be
convinced that the new behavior corresponds to the law. Accordingly, no framework exists
within which desuetude can operate in compliance with the doctrine of opinio
When those subject to the laws forget the past custom, the prior law effectively is not
changed by a contrary practice. If the people completely forget customary law, then as a
practical matter, the law does not and did not exist. In analyzing this issue, a theory of
obsolescence is unimportant because creating law where none existed before is the only
relevant matter. In this regard, historians should note that total amnesia of the
customary law can occur only in two particular circumstances. First, the past
behavior may have occurred very infrequently. As a result, historians must question
whether the behavior ever achieved the common consciousness necessary to become law.
Alternatively, the people may have gradually adopted a very different lifestyle with
respect to the past custom, e.g., perhaps as a result of migration. In that case,
historians should regard the new practice as law, not simply because new law has replaced
old law, but because law has been created for circumstances where no law previously
existed. In either event, when the people completely forget a rule or supposed rule of
customary law, the doctrine of opinio necessitatis unfortunately does not explain
how a subsequent contrary practice has, as law, replaced previously existing customary
Thus, the doctrine of opinio necessitatis excludes the possibility of changing
customary law by subsequent practice, both when the customary law is remembered and when
it is forgotten. If, as theorists likely would agree, customary law should correspond with
people's actions, then any theory of customary law must provide a means of changing the
law through contrary practice. Therefore, opinio necessitatis must be dismissed
on the basis of this failing.
Savigny, despite his powerful argument that opinio necessitatis does not fit
within the framework which historians usually attribute to customary law, retains the
notion. Savigny's solution rests on his [*566] general view of
law as the "spirit of the people."
Under this view, law arises not from individual acts of behavior but from common
consciousness. Individual acts of behavior do not create customary law but are merely
appearances or indications of a preexisting common conviction about the law. Under Savigny's
approach, therefore, the opinio necessitatis exists before the first relevant act
of behavior. Consequently, the first act does not rest on an error of law. Opinio necessitatis
is thereby saved, but only as a very different doctrine of the nature of customary law.
The validity of Savigny's view of custom and opinio necessitatis, however,
depends on the plausibility of his general theory of law which current legal philosophers
universally reject. Therefore, this article
does not further discuss Savigny's doctrine.
III. A PROPOSED THEORY TO REPLACE OPINIO NECESSITATIS
Under the preceding analysis, if the theory of customary law is to retain the power to
reflect changing practices or to explain the power of customary behavior to create law,
theorists must abandon the doctrine of opinio necessitatis. In addition to the
prior criticisms, this article raises further objections to the doctrine of opinio
necessitatis. The objections and proposed resolution reflect the reality that opinio
necessitatis simply cannot explain what actually happens in practice.
John Austin suggests a different theory which legal historians may find more acceptable
than opinio necessitatis. According to Austin, customary laws originate as rules
of positive morality which arise from the consent of the governed. However, for moral
rules to be transformed into positive laws, the state must establish these customary laws.
The state may establish customary laws either directly by statute, or indirectly by
judicial decree. Thus, under Austin's
approach, customary behavior does not make law; custom becomes law only when it is the
subject of statute or judicial decision.
Austin's theory is consistent only with his position that law is the command of the
sovereign. Under this view, a statute becomes law even before it is enforced by a court
decision. Scholars who do not
accept Austin's reductionist theory of law will find Austin's theory of custom
unacceptable. If one believes that other sources of law, such as custom, exist in theory,
then law may also potentially exist without benefit of a court decision. One may argue
convincingly that "it is precisely the binding force of custom which challenges
[Austin's] initial assumption itself," and that "he failed to explain
satisfactorily why the body of rules which he classified as positive morality' . . .
lacked the true character of law."
A second objection to Austin's theory concerns societal treatment of judicial decisions.
Societies that do not treat judicial decisions, even a consistent line of decisions, as
binding legal precedents may nevertheless treat decisions establishing a custom as
binding. From this viewpoint, a legal historian might claim that custom rather than
judicial precedent is law. In this system, when a court finds that a custom exists, the
subsequent decision based on that custom is not binding as a decision. Accordingly, the
court establishes the preexisting custom as a matter of fact, and the decision, which is
not law, merely confirms the preexisting law.
Although these two points detract from Austin's theory, other arguments support his
position. First, customary law often does not develop from a "general conviction of
law" held by a community. When a general conviction that a practice constitutes law
is missing, legal decisions play a fundamental role in determining the rule of customary
law. Thus, those living under customary law who wish to reduce the custom to writing
complain that the law is difficult to find, know, or remember. For example, the famous
thirteenth century Philippe de Beaumanoir justified his Coutumes de Beauvaisis by
stating: "it is my opinion and [that] of others also that all customs that are now
used [should] be written down and recorded so that they be maintained without change from
now on, because through memories that are liable to fade and human life that is short what
is not written is soon forgotten."
Moreover, in his Conseil, written about 1260, Pierre de Fontaines recorded the
customs of Vermondais and claimed that the old customs were much destroyed and that almost
all customs were defective. He attributes this disintegration in part to judges who
preferred their own wishes to the dictates of custom, in part to those who were more
attached to their own opinions than to the practices of earlier generations, and primarily
to the rich despoiling the poor and then the poor despoiling the rich. The country, de
Fontaines said, was almost without custom.
J. A. Brutails, in his celebrated work on the customs of Andorra, also demonstrates the
difficulty of knowing the coutours of customary law. He stresses that in a small
geographic area the number of lawsuits is limited, and that in the absence of any
methodical collection of decisions, the law announced in the cases fluctuates. He also
emphasizes that there often is disconcerting uncertitude regarding contemporary and
important matters. For instance, when Brutails asked prominent people, magistrates, former
magistrates, and judges to ennunciate a widow's rights in the property of her deceased
husband, he received five different answers.
Indeed, Brutails claims to have often heard that Andorra had no custom, but he insists
that Andorra seems no different than other customary systems. Despite numerous and
significant gaps in Andorran law, scholars have been uncertain whether the legal system
intended that these gaps be filled by reference to Roman, canon, or Catalan law. The
common view favored Roman law, but Brutails sought to demonstrate that Catalan law usually
prevailed. A much earlier work,
King Charles VII of France's Ordonnance de Montil-les-Tours, dated April 1453,
records a similar condition: "[I]t often happens that in one single region, the
parties rely on contrary customs and sometimes the customs are silent and vary at will,
from which great hardships and loss affect our subjects."
In the absence of official redactions of the customs which then govern as statutes, court
decisions embody the rules. As Philippe de Beaumanoir says in his unofficial redaction:
"[W]e intend to confirm a great part of this book by the judgments that have been
made in our time in the said county of Clermont."
The Maitre Echevin's preface to the 1613 official redaction of the customs of Metz, which
required forty-four years to compile, reflects both the difficulty of determining
customary law and the necessary reliance upon judicial decisions in doing so:
At last, gentle people, here is the methodical disposition, so passionately wanted, so
impatiently awaited, the hardwon redaction of the customs according to which our ancestors
so happily administered public business. The customs here, of course, cost much time to
lift them from the dust; if so many thorns (that you know about) had not been met with,
you would be right to be less pleased with your official, because, truth to tell, one is
not at all indebted for what one has rather dragged out than received. But apart from the
incredible work employed simply to set out various opinions so that they agree on the same
matter, there was need of several Hercules to overcome the difficulties, common and [*569]
frequent, as much in seeking out the articles in each chapter, as in verifying
them. This was not done by giving way to the opinions of individuals, but by a precise and
painful reading through of the judgments, memorials and instructions which mossy antiquity
left in the strong boxes of the town. Despite all this, the customs are dear to us for the
utility the public will receive from them.
Brutails claimed, and Ourliac recently
has agreed, that the idea of
legality is very obscure in Andorra. Brutails and Ourliac apparently believe both that
great doubt often exists in Andorra as to which legal rules are appropriate in a given
situation, and that ascertaining the precise legal rule to apply does not rank as a high
priority in general Andorran thinking. If this is a correct reading of the
Brutails-Ourliac position, their belief can be generalized. In customary systems, the
nature and application of legal rules are often uncertain, but this uncertainty is not
treated as a matter of great concern.
Customary law most often flourishes in small communities with a high degree of kinship,
where the law is not based on an academic tradition. Hence, there is a relatively small
number of disputes and, in a customary system, disputes delimit the scope of legal rules.
In the absence of a strong academic tradition, officials will be reluctant to generalize
from specific instances and to extract principles which can be used in different
situations. Moreover, those few important decisions that exist may not be adequately
recorded or easily accessible.
The example of Andorra as a living customary law system illustrates the relatively minor
role of legal principles in a customary law system. The first published Andorran decisions
started appearing in a journal, Revista juridica de Cataluna, only in 1963; only two collections
exist in book form. Although the collection of Carles Obiols i Taberner covers a
twenty-one year period from 1945 to 1966, it contains only ninety-six appellate decisions.
and commentary cover decisions on appeal to Perpignan from 1947 through 1970.
Significantly, both sets of reports each occupy only one slim volume.
Most importantly, there is relatively little demand for a precise knowledge of the legal
rules of a customary system. Many disputes in a small community are among relatives,
friends, or neighbors. These disputants must live on close terms with one another
afterwards, and they often have recourse to less formal means of dispute resolution.
Respected friends or relatives may be invited to adjudicate or a [*570] recognized
approach to adjudication may arise in a particular village. As a result, the appointed
adjudicators often reach a decision based on personal perceptions of fairness and reason
rather than by searching for a definitive legal rule. Furthermore, in a small community
where great flexibility is required, formal legal rules do not necessarily give the most
acceptable solution. If a problem situation occurs often enough, however, and if the same
decision-makers usually reach the solution, a custom may emerge.
In addition to the difficulty of ascertaining common practices, scholars must cope with
the tendency of customary law to originate not from what the people do, but from what the
people borrow from other localities. The standard practice, particularly common in
medieval France, in which one jurisdiction accepts the law of another system as its
residual custom, gives striking testimony to the importance of nonlocal custom. Nonlocal
custom plays an important role regardless of whether the outside customary system is the Coutume
de Paris, is a neighboring custom as in the pays de droit coutumier, or is
Roman law as in the pays de droit ecrit. This wholesale reception of outside
custom, though residual, is important for two reasons. First, reliance upon nonlocal
custom reduces the adjudicator's discretionary choices in an individual situation. Second,
the outside custom may have originated in a society based upon very different economic and
political characteristics, such as ancient Rome, or for a much larger, more commercial,
and more anonymous center, such as Paris.
Reliance upon nonlocal custom occurs even when a local patriot prepares an unofficial
collection of customs. For instance, modern scholars agree that by far the greatest part
of the Conseil of Pierre de Fontaines comes from Justinian's Digest and Code,"
even though the Conseil
was intended to be a practical work to use in training a friend's son in the local
customs. The same observations
apply to the contemporary Livre de Jostice et de Plet, a product of the Orleans
area, where the Roman and canon law origins of the rules are hidden and ascribed falsely
to French notables.
Moreover, unofficial collections incorporating both local and foreign customs may
indirectly create customary law. Of course, unofficial works would not themselves create
customary law, but the courts frequently treated the unofficial works as evidence of the
custom. In those instances, court decisions had a particular relevance: by adopting the
rules in the compilations, whatever the origin of the rules, courts expressed the rules as
In perplexing cases, the courts frequently based their decisions upon foreign customs.
Thus, Philippe de Beaumanoir also intended [*571] that
decision-makers use his compilation of custom "for doubtful cases in the said county,
by judgments of neighboring lordships."
Not only was a foreign source of law borrowed, and treated as the custom of the
borrowing jurisdiction, but the borrowed foreign
rule was actually that embedded in the foreign judgment. The borrowed rule,
however, would have the force of law only when a decision-maker incorporated it in a
judgment of the borrowing jurisdiction.
IV. ROLE OF JUDGMENTS IN CREATING CUSTOMARY LAW
The basis of local customary law is frequently treated as custom rather than judicial
precedent even though acceptance of the rule actually stems from local judgments rather
than from antecedent local behavior. This
treatment raises a question about the role of judgments in creating customary law. The
following series of propositions, beginning with those already established, both clarify
the question and suggest a resolution.
1. To become law, custom requires something more than behavior.
2. Opinio necessitatis fails to provide the extra factor required.
3. Court decisions declare customary law even when (a) custom is uncertain (and there is
no opinio necessitatis) and (b) there is no custom.
4. Proposition three is still accurate when, as in many systems, court decisions do not
make law; hence, we cannot simply say the court decision is the entire basis of customary
5. Custom officially written down as law is equal to law in the form of a statute; the
writing, however, is not proof that the custom was not previously law.
Propositions one through four were established earlier in this article. Proposition five
is self-evident. To these propositions we can add:
6. Court decisions are not law, and therefore cannot be the basis of custom becoming law.
But, if the decisions declare custom as law even without requiring preceding practice
(i.e., combining propositions three and four), then the official declaration of a rule as
customary law makes it law regardless of whether the behavior was customary.
Official recognition that particular normative behavior is [*572] customary makes
such behavior law. But official recognition also entails official acceptance. Hence, the
validity of this custom as law depends on its official recognition and acceptance.
7. It follows that in societies where decision-makers treat customary behavior as law,
there is also an attribution to the people of the power to make law by their tacit
8. But, this law is created only when decision-makers officially recognize or accept it.
Just as the opinion of a sovereign is not law until it is institutionalized by statute, so
behavior of the people is not law until institutionalized by an official court decision
which recognizes and accepts it.
9. As a corollary, if custom has not been expressed in a judicial decision, and hence is
not law, but is set out in an official redaction, the custom becomes law but as statute
rather than as custom.
This interpretation of the nature of customary law incorporates a theory for the creation
or alteration of customary law. Normative customary behavior becomes customary law when it
is recognized by the courts as law. Accordingly, the actors need not believe that they are
already acting in accordance with an existing rule of law. So long as the courts treat the
custom as law, the custom is the accepted customary law. Should the courts hold that the
custom has changed, however, then the new ruling becomes the customary law.
These findings on the nature of customary law might support Austin's theory that law
consists of the commands of a sovereign that are backed by sanctions. In this instance, a
sovereign is defined as someone whose commands are habitually obeyed and who does not
habitually obey anyone else. At this preliminary stage, however, this article is not
concerned with the validity of Austin's theory as a whole. Rather, this article, for the
sake of argument, will for the moment accept his proposition that when judges made a legal
rule, that rule is established by the sovereign legislature. If there can be no
customary law without a court decision, the concern at this point is whether customary
law is at least as much a command of the sovereign as is binding precedent.
Only three factual situations need be considered in assessing the nature of the
sovereign's command. First, some writers, notably Vinnius, argue that there can be
no customary law under an emperor. In situations where an empire exists, acceptance of
this doctrine creates no problem for Austin with regard to custom. Second, in some
circumstances customary law is accepted and judicial precedent is binding. This situation
also does not create a problem for Austin because decision-makers may resolve any conflict
by recognizing that custom forms a rule of law when incorporated in a binding precedent.
Third, occasionally customary law is accepted and judicial precedent is not otherwise
binding. In this instance, the people as a whole are not the sovereign in Austin's sense.
Their behavior creates law, but only at the moment when it is recognized and accepted by
the court; judicial acceptance is a necessary precondition to creation of law. Hence,
insofar as Austin is correct in arguing that the sovereign's acceptance of a court
decision as creating law is thereby a command of the sovereign, a court decision accepting
custom as law is equally a command of the sovereign. This point is significant because
critics frequently argue that one of Austin's major weaknesses is precisely the difficulty
of fitting customary law into his theory.
Austin's theory implicitly assumes that all law is legislation and that judges, insofar as
they create law, are legislators. My position is different. I agree that binding judicial
precedent is both law-making in its own right and a source of law distinct from
legislation. Judicial law-making, however, requires that the process be accepted by the
sovereign as an appropriate method of creating law. Similarly, custom is a separate source
of law distinct from both legislation and judicial precedent. But like judicial precedent,
custom must be accepted by the sovereign in order to constitute law. To become law,
custom, like legislation and binding precedent, must be clothed with the requisite form
which marks its official acceptance by the sovereign. This requisite form requires that
adjudicators incorporate custom in a judicial decision. A society may accept custom as law
when incorporated in a judicial decision but deny law-making effect to precedent, thereby
demonstrating that custom as a means of making law is not simply subsumed into
The conclusions that customary law does not necessarily derive from what people do and
that official judicial decisions declare the law illuminate other problems with customary
law. To begin with, the legal difficulties described by F. Pollock and F.W. Maitland become understandable
in light of these conclusions. Pollack and Maitland report that in the Middle Ages,
neighboring villages were frequently inhabited by persons of the same race, religion, and
language, who were subject for centuries to the same economic conditions. Yet, neighboring
villages often had very different rules; for example, for the central institution of
matrimonial property. The villages initially may have shared common means of arranging
family property holding, but in each village one approach eventually became fixed as law
through the process of judicial decision-making.
The final result in any one place, therefore, will contain some element of the arbitrary.
Secondly, the theory of judicially institutionalized customary law sheds new light on a
common German medieval practice of resolving legal disputes. Independent towns governed by
customary law selected a mother town to whose Schoffen, or adjudicatory body, the
daughter town submitted unresolved legal issues. " The daughter
town may have preferred, for various reasons, that the mother town provide a ruling. For
example, the daughter town may not have had a dominant custom or the custom may have been
unsettled or unknown. Further, the mother town's Schoffen may have had high prestige or
the local Schoffen may have preferred to distance themselves from local disputes. Yet
regardless of how the question to the Schoffen might be framed, the daughter town is not
seeking to know its own customary practice.
The practice of submitting disputes to a neighboring town is a particular example of a
more general phenomenon: local areas often display lack of interest in establishing local
custom. The frequency of borrowing another's custom is itself an example of this lack of
interest. A further illustration is provided by the popularity of the Sachsenspiegel.
This unofficial statement of early thirteenth century practice in the bishoprics of
Magdeburg and Halberstadt was widely used in northern Germany, Poland, the Low Countries,
Yet another example of lack of interest in establishing local custom is the enormous
length of time that elapsed between the French royal command to reduce customs to writing
and the completion of that effort. In 1453, Charles VII's Ordonnance of
Montil-les-Tours [*575] required the
redaction of the customs in each district, but a century passed before most of the work
was completed. The delay is
attributable not only to the magnitude and difficulty of the task but also to a frequent
lack of interest in establishing the custom.
Although a doctrine of judicially institutionalized customary law resolves a number of
issues in customary law theory, the doctrine raises other questions. For instance, the
traditional explanation for the scarcity of legislation on private law during the Middle
Ages may need to be reexamined. The traditional explanation is that great foci of
centralized power were lacking, and that kings and other magnates were weak. In some instances this
may be a complete explanation, but in other instances the traditional view is clearly
inadequate. For instance, magnates frequently granted charters to towns and issued
statutes on matters relating to public law. And, as we have seen, it is unlikely that
townspeople were so fiercely attached to their customs that they would have bitterly
resented magnates' power to legislate on private law. In fact, as the doctrine of
judicially institutionalized customary law teaches, people often displayed no great
attachment to local customs. The simplest
explanation is that magnates frequently had more interesting, more exciting, and perhaps
more important things to occupy their time than legislating private law for their
A major problem for any theory of customary law is determining the nature of the
additional factor required to transform custom into law. The doctrine of opinio
necessitatis generally has replaced earlier consent theories, but a major flaw of the
opinio necessitatis doctrine remains. The doctrine fails adequately to
incorporate the creation of new customary law or the deletion of obsolete customary law.
Neither deseutude nor Savigny's theory of common consciousness sufficiently resolve the
logical failings of opinio necessitatis.
Austin's work suggests that custom becomes law only by the additional factor of state
confirmation. Redactions of customary law show that, although the basis of customary law
is treated as custom rather [*576] than judicial
precedent, acceptance of the rule often arises from official judgments rather than from
antecedent local practices. Court decisions, not law themselves, function as official
sovereign recognition and acceptance of rules of custom as law. Court decisions transform
rules of custom into law, regardless of whether the antecedent custom was actually
recognized as law. Customs do not become law until institutionalized by inclusion in an
official court decision. This theory of customary law may help to explain several
otherwise problematic aspects of medieval and practice.
n1. In view of the
theoretical difficulties encountered in determining when a law, the nature of custom in
modern "tribal societies" is not discussed here. For the development of a theory
of custom in Roman law, insofar as there is one, see Norr, Zur Entstehung der
Gewohnheitsrechtlichen Theorie, in FESTSCHRIFT FUR W. FELGENTRAEGER 353 (1969). For a
very different view of the formation of customary rules, particularly in international
law, see J. FINNIS, NATURAL LAW AND NATURAL RIGHTS 238 (1980). This paper also does not
discuss custom as a source of international law.
n2. EPITOME ULPIANI 4.
n3. See, e.g.,
INST. JUST. 1.2.9.
n4. See, e.g.,
DIG. JUST. 22.214.171.124 (JULIAN DIG. 84). The accuracy of Julian's account of the people's
role in statute-making, or of custom bringing about the deseutude of statute, need not be
n5. Because this is
not directly an article on the history of legal theory, I have done little more than read
the appropriate pages in the GLOSS and typical authors such as Oinotomus, Wesembecius, J.
Voet, Vinnius, and Heineccius.
n6. See, e.g.,
K.C.W. KLOTZER, VERSUCH EINES BEYTRAGS ZUR REVISION DER THEORIE VON GEWOHNHEITSRECHT 189 passim
(Jena 1813); S. BRIE, DIE LEHRE VON GEWOHNHEITSRECHT 1 (1899). Rudolf von Jhering
described custom as the "pet" of the German Historical School. See R.
VON JHERING, GEIST DES ROMISCHEN RECHTS P2.1 (5th ed. 1894).
n7. I translated this
quotation from K. LARENZ, METHODENLEHRE DER RECHTSWISSENSCHAFT 338 (2d ed. 969) (emphasis
in original) [hereinafter cited as K. LARENZ, METHODENLEHRE]. See also K. LARENZ,
ALLGEMEINER TEL DES DEUTSCHEN BURGERLICHEN RECHTS 10 (5th ed. 1980). In later editions
Larenz is much less explicit, although he seems to hold basically the same opinion. See,
e.g., K. LARENZ, METHODENLEHRE, supra, at 345 passim (4th ed.
1979). Larenz expressly adopts Norr's view that the theory of customary law, as such, is
n8. K. LARENZ,
METHODENLEHRE, supra note 7, at 338. See supra text accompanying note 7.
n9. 1 F. SAVIGNY,
SYSTEM DES HEUTIGEN ROMISCHEN RECHTS 174 (Berlin 1840).
n10. See, e.g.,
Dig. JUST. 1.3.39. This view is generally accepted within the tradition.
n11. No comparison can
be drawn between desuetude of customary law and that of statutes. With statutes, there is
no need for a belief that the contrary action accords with the law.
n12. See, e.g.,
C.K. ALLEN, LAW IN THE MAKING 136 (7th ed. 1964).
n13. 1 F. SAVIGNY, supra
note 9, at 171.
n15. Id. at
n16. See, e.g.,
C. K. ALLEN, supra note 12, at 87. Yet oddly, Austin's theory survives
indirectly, without the theoretical trappings, in a number of writers. For instance, see
the authors quoted in A. WATSON, SOCIETY AND LEGAL CHANGE 1 (1977); L. FRIEDMAN, A HISTORY
OF AMERICAN LAW 595 (1973). In a curious way, Calabresi seems a modern distorting mirror
of Savigny. For Calabresi, the judges -- like jurists -- "represent" the people
at one level, the current "legal landscape" generally reflects popular desires,
and legislation inhibits law from giving the people what they want and need. See
G. CALABRESI, A COMMON LAW FOR THE AGE OF STATUTES (1982).
n17. J. AUSTIN, THE
PROVINCE OF JURISPRUDENCE DETERMINED 30, 163 (1954); 2 LECTURES ON JURISPRUDENCE 222
n18. Gray argues that
statutes are not law but only sources of law, because their meaning is declared by the
courts and "it is with the meaning declared by the courts, and with no other
meaning, that they are imposed upon the community as Law." R. GRAY, THE NATURE
AND SOURCES OF LAW 170 (2d ed. 1921) (emphasis in original).
n19. C.K. ALLEN, supra
note 12, at 70.
n20. P. DE BEAUMANOIR,
COUTUMES DE BEAUVAISIS § 71 (n.d.).
n21. P. DE FONTAINES,
CONSEIL ch. 1, § 3 (n.d.).
n22. J. BRUTAILS, LA
COUTUME D'ANDORRE (1904).
n23. Id. at
n24. Id. at
n25. KING CHARLES VII,
ORDONNANCE DE MONTIL-LES-TOURS 125 (France 1453).
n26. P. DE BEAUMANOIR,
supra note 20, at 6.
n27. The Preface is
n28. J. BRUTAILS, supra
note 22, at 342.
n29. P. OURLIAC, LA
JURISPRUDENCE CIVILE D'ANDORRE -- ARRETS DU TRIBUNAL SUPERIEUR DE PERPIGNAN: 1947-1970, at
12 n.7 (1972).
n30. Further reports
appear in subsequent volumes.
n31. C. TABERNER,
JURISPRUDENCIA CIVIL ANDORRANA -- JUTJAT D'APPELLACIONS: 1945-1966 (1969).
n32. See A.
WATSON, SOURCES OF LAW: LEGAL CHANGE AND AMBIGUITY 45 (1984).
n33. P. DE FONTAINES, supra
note 21, ch. 1, § 2.
n34. See A.
WATSON, supra note 32, at 46.
to P. DE BEAUMANOIR, supra note 20.
n36. Not all
contemporaries saw borrowing of a neighbor's custom as borrowing it for the purpose of
adopting it as the custom of the borrower. See G. COQUILLE, COUTUME DE NIVERNAIS
n37. Of course one
should not take this analysis as meaning that customary law never derives from local
behavior. But where it does, there are nevertheless great difficulties in regarding opinio
necessitatis as the key factor that turns behavior into law. The elaborate devices
designed to discover what the nature of the custom was, such as the "enquete par
tourbes" in France or the "Weistumer" in Germany, amply
demonstrate that a behavior was not necessarily known to be law, or accepted and practiced
as law by persons sharing the same law.
n38. Critics may
object that although official recognition transforms into customary law practices that
were not previously customary, habitual normative behavior may nonetheless be law as
custom prior to official recognition. This objection is especially powerful if the
practice was universally regarded as the custom. The objection, though prima facie
plausible, is ultimately untenable. Suppose a case involving a practice universally
regarded as custom comes before a court and the court rejects the behavior as
incorporating customary law. In that case, one must conclude that the custom cannot be
law. Yet, if the decision does not create law then the decision cannot change the law;
hence, the normative behavior was not customary law before the decision. The official
recognition of normative behavior as customary law makes such behavior law.
n39. The text of
Justinian's Institutes explains that the statement "[t]he will of the
Emperor has the force of statute" means that the emperor's will comes to have the
force of law when it is couched in the proper institutionalized form. INST. JUST. 1.2.6.
Thus, "[d]eeply rooted custom is observed as a statute," similarly means, as we
have seen, that custom comes to have legal effect when it is "expressed in the proper
institutionalized form, namely, in judicial decision. DIG. JUST. 126.96.36.199. If the statute
incorrectly specifies the will of the Emperor, however, the accepted statutory meaning
prevails; likewise, if there is no custom, the accepted judicial interpretation prevails.
n40. J. AUSTIN, supra
note 17, at 31.
n41. VINNIUS, IN
QUATTUOR LIBROS INSTITUTIONUM IMPERIALIUM COMMENTARIUS ad 1.2.7.
n42. The Bavarian
civil code of 1756 expressly requires both the will of the people and the consent of the
ruler for customary law. See CODEX MAXIMILIANUS BAVARICUS 1.2, § 15 (n.p. 1756).
n43. See, e.g.,
A. WATSON, THE NATURE OF LAW 3 (1977). One difficulty remains in accepting Austin's theory
as a whole. Austin views binding judicial precedent and customary law as equivalent forms
of law-making in the sense that both require the consent, acceptance, and tolerance of the
sovereign to be law. Of course, that consent, acceptance, and tolerance might be withheld.
Nonetheless, consent, acceptance, and tolerance are not equivalent to a command.
n44. 2 S. MILSOM,
HISTORY OF ENGLISH LAW 399 (2d ed. 1968).
n46. For a description
of this practice, see A. WATSON, supra note 32, at 31.
n47. Of the two parts
of the Sachsenspiegel, one part survives in over 200 manuscripts, and the other
in almost 150. The Sachsenspiegel has been translated numerous times. See id.
at ch. 2.
n48. Id. at
n49. All this alerts
us to the danger of misconstruing similarity of customary law with societal similarity.
Although scholars refer to "families" of customary law, one should not deduce
that the members of one legal family group are closer to each other in economic, social,
and political structure than they are as a group to the members of other legal families.
The legal family may result more from the choice of legal approaches than from
similarities of customs.
n50. See F.
TOMAS Y VALIENTE, MANUAL DE HISTORIA DEL DERECHO ESPANOL 133 (3d ed. 1981).
n51. Certainly the
compilers of unofficial collections of customary law frequently praise the quality and the
descent from their forefathers. But we cannot generalize from these writers. They wrote
these works because they were attached to the customs, but this does not imply that the
same feeling existed in other members of the community. Indeed, the authors often lament
that the customs are not being kept.