Now his parents went to Jerusalem every year at the Feast of the Passover. And when he was twelve years old, they went up according to custom. And when the feast was ended, as they were returning, the boy Jesus stayed behind in Jerusalem. His parents did not know it, but supposing him to be in the group they went a day’s journey, but then they began to search for him among their relatives and acquaintances, and when they did not find him, they returned to Jerusalem, searching for him.
— Luke 2:41-45