I Kings 12:28, 30, 33

Therefore the king asked advice, made two calves of gold, and said to the people, “It is too much for you to go up to Jerusalem. Here are your gods, O Israel, which brought you up from the land of Egypt!”

Now this thing became a sin, for the people went to worship before the one as far as Dan.

So he made offerings on the altar which he had made at Bethel on the fifteenth day of the eighth month, in the month which he had devised in his own heart. And he ordained a feast for the children of Israel, and offered sacrifices on the altar and burned incense.