In 1223, three years before his death, Francis wanted people to grasp more deeply the humility and poverty in which Jesus Christ had been born. So, as Christmas approached, he asked his friend John of Greccio to prepare a cave with a manger, hay, and animals, to simply represent the birth of the Lord. Francis wanted everyone to see with their own eyes the hardship and poverty into which the Son of God had come into the world. 

On Christmas night, many friars and local people came to the site carrying torches and singing praises. The Eucharist was celebrated over the manger, and Francis, vested as a deacon, proclaimed the Gospel of Jesus's birth. He then preached with great emotion about the Child of Bethlehem, speaking of him with such love and tenderness that those present were deeply moved. According to Thomas of Celano, many felt an extraordinary spiritual joy that night and renewed their faith. 

The Greccio celebration is considered the origin of the Nativity scene tradition. For Francis, however, it was not merely a representation, but an invitation to draw close to a humble and poor Christ. With that gesture, he wanted to remind people that God chose not wealth or power, but the simplicity of a stable to show his love for all humanity. Today, more than eight centuries later, the memory of the Christmas at Greccio still helps millions of people live the true meaning of Christmas.