Ahead of his return to the hermitage, two weeks before Christmas, Francis asked his friend, Lord of Greccio Giovanni Velita, to prepare a cave with live animals and a hay-filled manger.

Source: https://www.ncregister.com/cna/st-francis-and-the-story-of-the-first-nativity-scene-uwazrnkq

One of the bystanders, a knight of Greccio named John of Velita, told of a vision of the infant Jesus in the manger as Francis preached.

Source: https://www.mississippicatholic.com/2023/12/04/thanks-to-st-francis-800-year-tradition-of-nativity-scene-born/