1 Kings 12:31-32

31Jeroboam also built shrines on the high places and appointed from every class of people priests who were not Levites. 32And Jeroboam ordained a feast on the fifteenth day of the eighth month,1 like the feast that was in Judah, and he offered sacrifices on the altar; he made this offering in Bethel to sacrifice to the calves he had set up, and he installed priests in Bethel for the high places he had set up.