The most important chapel of Santa Trėnita is that of the Sassetti family, the second on the right after the choir. This was covered in frescoes that tell the story of St Francis of Assisi by Domenico Ghirlandaio in around 1485.

Ghirlandaio was, along with Botticelli, the greatest painter of the late 15th century, and the relaxed narrative style of this Renaissance painter is extremely pleasing. You can see this clearly in the lunette where he painted the Granting of the Rules of the Franciscan Order.
Notice the portraits of Lorenzo the Magnificent with his family and courtiers, among whom is the poet Angelo Poliziano. Notice also the exact rendering of Piazza della Signoria. The altar panel is also by Ghirlandaio.