From Josephus
  1. When he was dead, and had left a young son, who was called Onias [II], Simon’s brother Eleazar...took the high priesthood” [whether as “regent” specifically is not said]. Josephus AJ XII.II.5
  2. It was high priest Eleazar with whom Ptolemy [II] Philadelphus arranged for a Greek translation of the Hebrew scriptures.
  3. While Onias [II] was high priest, Antiochus [III] and Ptolemy [V] reconciled their conflict and ”made a league”--Antiochus gave Ptolemy his daughter Cleopatra [I] to wife and yielded up as her dowry “Celesyria, and Samaria, and Judea and Phoenicia.... ... This happened when Onias [II 2] was high priest.” Josephus AJ XII.IV.1.
  4. “[A]fter Eleazar’s death, his uncle Manasseh took the priesthood.” Loc. cit.

Taken from: JewishEncyclopedia.com