Dimensions: 36 x 46 cm.

The altarpiece, one of the most grandiose of the Quattrocento altars, was executed after the decision of Cosimo de' Medici in 1438 to transfer to Cortona the triptych which served as main altar of the convent church. It depicts, in the front, the kneeling Sts Cosmas and Damian, then in the second row, from the left: Sts Lawrence, John the Evangelist, Mark, Dominic, Francis and Peter the Martyr. It is assumed that the figure of St Cosmas is the likeness of Cosimo de' Medici. In the lower center a Crucifixion with golden background can be seen.

This picture is the second from the right on the predella. The legend of Sts Cosmas and Damian, twin brothers who were famed for making no charges for their services as physicians, is outlined in the predella panels of this San Marco altarpiece. Several attempts to put them to death failed, until the last, pictured here. The final moments of the two brothers are shown set against one of Angelico's finest landscapes. Outside a town with fortifications akin to those of Jerusalem in his Deposition, the two saints wait to join the three headless figures in the foreground. The greatest emphasis falls on the one who kneels directly in front of a row of five cypresses which runs parallel to the picture plane. The trees can be taken to symbolize the five being executed.