In artistic representations, he can be recognized by his holding an iron knife "(secespita)" or the "patera", and the distinctive robes or toga with part of the mantle covering the head "(capite velato)", in keeping with Roman practice. The Pontifex was not simply a priest. He had both political and religious authority. It is not clear which of the two came first or had the most importance. In practice, particularly during the late Republic, the office of Pontifex Maximus was generally held by a member of a politically prominent family. It was a coveted position mainly for the great prestige it conferred on the holder; Julius Caesar became pontifex in 73 BC and pontifex maximus in 63 BCE. The major Republican source on the pontiffs would have been the theological writings of Varro, which survive only in fragments preserved by later authors such as Aulus Gellius and Nonius Marcellus. Other sources are Cicero, Livy, Dionysius of Halicarnassus, Valerius Maximus, Plutarch's "Life of Numa Pompilius", Festus' summaries of Verrius Flaccus, and in later writers, including several of the Church Fathers. Some of these sources present an extensive list of everyday prohibitions for the Pontifex Maximus; it seems difficult to reconcile these lists with evidence that many Pontifices Maximi were prominent members of society who lived normal, non-restricted lives. The number of Pontifices, elected by "co-optatio" (i.e. the remaining members nominate their new colleague) for life, was originally five, including the "pontifex maximus". The "pontifices", moreover, could only come from the old nobility, the patricians. However, in 300–299 BCE the "lex Ogulnia" opened the office of Pontifex Maximus to public election and permitted the "plebs" (plebeians) to be co-opted as priests, so that part of the exclusivity of the title was lost. But it was only in 254 BCE that Tiberius Coruncanius became the first plebeian Pontifex Maximus. The "lex Ogulnia" also increased the number of pontiffs to nine (the "pontifex maximus" included). In 104 BCE the "lex Domitia" prescribed that the election of all pontiffs would henceforward be voted by the "comitia tributa" (an assembly of the people divided into voting districts); by the same law only 17 tribes, chosen by lot from the 35 tribes of the city, could vote.