Caesar, to whom we can now turn, was born on 12 July 100. The year is unanimously attested by our sources: see Groebe, RE 10.2 (1919) 187, in an article still worth reading (186-259). Mommsen tried to impose 102, Carcopino suggested 101, but these attempts to abandon the sources, based on the leges annales, may be ignored. (There are other ways of explaining the discrepancy: see already Zumpt 1874; later explanations abound.)
The date has been debated, and a mistaken date now prevails in (especially German) scholarship. The true date is assured by a precise quotation (though in indirect speech) by Macr. Sat. 1.12.34, of a law passed by the consul M. Antonius (i.e. in 44), changing the name of the month Quintilis to Iulius, ''because in that month, on the fourth day before the Ides (i.e. the 12th), Iulius was born'' (quod hoc mense a.d. quartum idus Quintiles Iulius procreatus sit: the numeral is written out in full and there are no textual variants). All our other sources agree on the date (see the full list in Degrassi 1963: 13.2, 189, 208, 481-2), down to John the Lydian in the sixth century AD, with the sole exception of Dio Cassius, in the third century, who gives 13 July, adding the tale that the date was officially changed to the 12th by a law of ''the Triumvirs.'' (He cites no source.) There should be no doubt that this cannot stand against the law of M. Antonius.
Caesar's first public appearance was in his seventeenth year (see Suet. Iul. 1.1), when the consul L. Cinna designated him flamen Dialis (priest of Jupiter), one of the most venerable of Roman priesthoods, the holder of which had to be married to a Patrician wife. Caesar therefore broke his engagement to a wealthy woman of equestrian family, arranged when he was still a child, and married Cinna's daughter Cornelia. (Plut. Caes. 5.3, implies that Caesar had actually married Cossutia, but a divorced man could not be flamen Dialis.) The priesthood thus conferred on the young man (there is no doubt that he was actually appointed: see Suet. Iul. 1.2) gave him immense distinction, but its taboos would debar a conscientious holder from a political career. (See RE, 6.2486-91 (Ernst Samter, 1909) s.v. Flamen Dialis, still one of the best treatments.) In view of the relative obscurity of that branch of the Caesares Cinna no doubt did not foresee a chance of a major career for the young man and tried to compensate by giving him the highest non-political honor.
When Sulla assumed the dictatorship after defeating the Cinnani (82), he annulled all the acta of Cinna, including Caesar's appointment, and ordered him to divorce Cinna's daughter. But Caesar refused, probably on the ground that the flamen Dialis was not allowed to divorce his wife. By thus in fact denying the legitimacy of Sulla's annulment of his appointment, hence by implication of all of Cinna's acta, Caesar was showing extraordinary courage. Sulla was practically forced to put him on his proscription list. Escaping from Rome, Caesar spent a short time in hiding, bribing his pursuers, so the Caesar myth alleges. (This is an example of how the myth pervades our accounts and makes it difficult to get at the facts. It cannot be true, since confiscation of his fortune went with his proscription, and he cannot have had the hefty sum such bribery would need with him on his flight.)
Meanwhile some relatives of his among the highest nobility (Suet. Iul. 1.2 found only two names) persuaded Sulla to relent. They were supported by the Vestal Virgins, no doubt in contact with Caesar through his priesthood. A compromise was reached: he agreed to resign his priesthood, which would in any case have made an official career impossible, but was allowed to keep his wife and no doubt to regain his possessions. Sulla’s reported remark, that there were many Mariuses in the young man, is clearly part of the myth. Sulla in fact never executed a fellow Patrician: the most striking example is L. Scipio Asiagenus, who actually broke a treaty with Sulla, but was allowed to retire into comfortable exile at Massilia.