Abstract

The first text of Justinian’s sixth century Digest records that Ulpian, the leading lawyer from Syria and counsellor to successive emperors of the Severan age (AD 193-235), related the term ‘law’ to four elements: art, religion, ethics and philosophy.2 Law is the art of the good and equitable, of which lawyers can well be called priests. They cultivate justice and the knowledge of right and wrong, and aim, unless Ulpian is mistaken, at the true philosophy.3 He goes on to say that private law is collected from three sources: natural law,4 the law common to all communities (ius gentium) and the law specific to each community (civil law).5 Gaius, a generation earlier, listed two sources: the civil law of each community and the ius gentium.6 He recognized, however, the existence of natural law which, so far as performing a ‘natural obligation’ is concerned, cannot be changed by civil law.7 At times he identifies natural law with ius gentium.