1 Kings 12:31-32

31And he made an house of high places, and made priests of the lowest of the people, which were not of the sons of Levi.

32And Jeroboam ordained a feast in the eighth month, on the fifteenth day of the month, like unto the feast that is in Judah, and he offered upon the altar. So did he in Beth–el, sacrificing unto the calves that he had made: and he placed in Beth–el the priests of the high places which he had made.12