I RE 12:32

Geroboamo ancora ordinò una festa solenne, al quintodecimo giorno dell'ottavo mese, simile alla festa chi si celebrava in Giuda; ed offeriva offerte sopra un altare. Così fece in Betel, sacrificando a' vitelli ch'egli avea fatti; e costituì in Betel i sacerdoti degli alti luoghi ch'egli avea creati.

And 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.