Legend of Saint Francis 15: Sermon to the Birds. One of 28 frescoes in a series by Giotto in the Upper Church (1297-99). St. Francis came across a flock of birds that did not fly away at his approach. He gave a sermon to the expectantly waiting creatures, who only left after receiving his blessing. Giotto emphasizes the extraordinary nature of the event through the reaction of a secondary figure, a Franciscan friar, who looks surprised and astonished.