The Law 153
simple, perhaps customary, law which was not written down and which gov-
erned everyday legal business in the western Roman provinces from the 4th to
the 6th century.15 It was an evolution or, depending upon one’s perspective, a
degeneration of purely ‘classical’ Roman Civil Law, that is, the law that origi-
nally applied to the city of Rome.16
But as the application of this law was gradually extended to encompass all
Roman citizens living in outlying provinces, it gradually came to take account
of and to be influenced by custom or provincial practice in a process com-
monly referred to as ‘vulgarization’. Prior to the granting of citizenship to all the
inhabitants of the empire, provincial communities were permitted to continue
observing their own local systems of law and custom, provided they were not
incompatible with Roman rule. As citizenship was gradually extended to ever
increasing numbers of provincials, culminating in 212 with Caracalla’s consti-
tutio Antoniniana, which granted Roman citizenship to all free inhabitants of
the empire, provincial communities were required to adopt and apply the Civil
Law, the rules and procedures of which were largely unknown to them. Given
that the inhabitants of these communities were often reluctant to abandon the
norms by which they had been governed in the past, elements of these local
systems gradually crept into the Civil Law. Over time, Rome’s law lost its classi-
cal ‘purity’ and became ‘vulgarized’.
The most influential voice for defining vulgar law has belonged to Ernst
Levy, who drew attention to the vulgarizing tendencies inherent in the Roman
laws of property that slowly emerged in the West over the course of the 3rd and
4th centuries. Vulgarizing tendencies, Levy claims, had existed at all times, but
classical jurisprudence kept them in check. Although vulgar law penetrated
even the legislation and was taken over by the elementary books for practitio-
ners and students (for example, the post-classical collection of legal opinions
attributed to the jurist Paul, or the Epitome Gai—an abridged version of the
Institutes that did away with all of Gaius’ complex explanations of the law), the
emperors of the 3rd century strove against this dissolution of the pure Roman
law. The chief protagonist of this fight was Diocletian (r. 284–305), and with his
15 Brunner, Zur Rechtsgeschichte der römischen, pp. 113, 119; id., Forschungen zur Geschichte,
p. 607 n. 1. The fundamental study of the development of Roman law in the East remains
that of Mitteis, Reichsrecht und Volksrecht. Here, the focus is on the influence of peregrine
law on classical notions and principles of Roman law. For a review of the scholarship see
Liebs, “Roman Vulgar Law”, pp. 35–53.
16 For this definition and a discussion of ius civile, see Mousourakis, Historical and
Institutional Context, pp. 22–4; Schiller, Roman Law, pp. 366–8, 525–7; Kaser, Römische
Rechtsgeschichte, pp. 130–3.