4. These men were A. Claudius, T. Genutius, P. Sextius, Spur. Viturius, C. Julius, A. Manlius, Ser. Sulpitius, P. Curiatius, T. Romilius, Sp. Postumius. These were the decemvirs chosen to write the laws.
5. The consul Pompeius was the first who wished to arrange the laws systematically, but he did not persevere, through fear of detractors. Then Caesar began to do it, but he was slain.
6. By degrees the old laws became obsolete through time and neglect; but a mention of them seems necessary although they are not in use now.
7. The new laws began with the emperor Constantine and the rest who followed him, but they were confused and in disorder. Later, in imitation of Gregorianus and Hermogenianus, the younger Theodosius arranged a code of constitutions from the time of Constantine, under the title of each emperor, which he called Theodosian from his own name.
Chapter 2. On laws human and divine.
1. All laws are either divine or human. Divine laws depend on nature, human laws on customs; and so the latter differ, since different laws please different peoples. Divine law is fas; human law is jus. To pass through another’s property is of divine but not of human law.
Chapter 3. On the difference between jus, leges, mores.
1. Jus is the general term and lex is a kind of jus. Jus is so-called because it is just (justum). All jus is made up of laws and customs.
2. Lex is the written ordinance. Mos is custom approved by its antiquity, or unwritten lex. For lex is derived from legere (to read), because it is written.
3. Mos is old custom and is drawn merely from mores. Consuetudo (custom) is a sort of jus established by mores, which is taken instead of lex when lex fails. And it makes no difference whether it depends on writing or reason, since reason commends written law also.