Cosimo employed Fra Angelico to paint more pictures for the convent. All the cells for the friars were built upstairs around the sides of a square courtyard with a garden in the middle (called a cloister). On the wall at the top of the stairs, Fra Angelico painted a fresco of the Angel Gabriel announcing the birth of Jesus to the Blessed Virgin Mary. This is one of his most famous pictures. Fra Angelico then began to paint a picture in each of the monk's cells. Each cell has large picture with a round top on the wall beside the window. At least six of these paintings were done be by Fra Angelico, and others were done by artists who copied his style of painting. These pictures were to help the friars with their prayers.