Flavius Josephus, Antiquities of the Jews
William Whiston, A.M., Ed.

[224] AND now I think it proper and agreeable to this history to give an account of our high priests; how they began, who those are which are capable of that dignity, and how many of them there had been at the end of the war. In the first place, therefore, history informs us that Aaron, the brother of Moses, officiated to God as a high priest, and that, after his death, his sons succeeded him immediately; and that this dignity hath been continued down from them all to their posterity. Whence it is a custom of our country, that no one should take the high priesthood of God but he who is of the blood of Aaron, while every one that is of another stock, though he were a king, can never obtain that high priesthood. Accordingly, the number of all the high priests from Aaron, of whom we have spoken already, as of the first of them, until Phanas, who was made high priest during the war by the seditious, was eighty-three; of whom thirteen officiated as high priests in the wilderness, from the days of Moses, while the tabernacle was standing, until the people came into Judea, when king Solomon erected the temple to God; for at the first they held the high priesthood till the end of their life, although afterward they had successors while they were alive. Now these thirteen, who were the descendants of two of the sons of Aaron, received this dignity by succession, one after another; for their form of government was an aristocracy, and after that a monarchy, and in the third place the government was regal Now the number of years during the rule of these thirteen, from the day when our fathers departed out of Egypt, under Moses their leader, until the building of that temple which king Solomon erected at Jerusalem, were six hundred and twelve.