Aaronic priesthood. The authority to perform certain ecclesiastical tasks, allegedly bestowed by John the Baptist onto Joseph Smith and his friend Oliver Cowdery on May 15, 1829. Baptized Mormon males 11 years and older are eligible to receive this priesthood. Known as the lesser of two priesthoods held by Mormon males (Priesthood and Church Government, p. 106).  

According to the Bible, only for Levites who were direct descendants of Aaron, the brother of Moses, were associated with this. Numbers 3:6-12 makes it clear that only those in the line of Aaron were to hold the Levitical Priesthood.