The age of eligibility for the office is not fixed in the Law; but according to rabbinical tradition it was twenty.[7] Aristobulus, however, was only seventeen when appointed by Herod;[8] but the son of Onias III was too young (νηπιος) to succeed his father.[9] The age a Levite entered the priesthood was 30 years of age (Numbers 4:3,30).