At the time when Joseph, Mary and Jesus were going to Egypt, Herod waited for those wise men to come back, but they tricked him. They didn’t come back to him. Then he got really angry. He remembered their story about when they first saw the star, so he sent his soldiers to Bethlehem, and he told them to kill all the little boys up to 2 years old. So they killed all the little boys around Bethlehem. Herod wanted to make sure that Jesus was dead.