Donatello's Ascension of St. John the Evangelist belongs within the larger sepulchral iconography of the Old Sacristy of San Lorenzo. In Donatello's relief, there is a donor-like figure that has not been discussed by scholars. This article argues that this figurę most probably represents Giovanni di Bicci de' Medici, the original patron of the sacristy, and that Donatello's Ascension formed part of a posthumous commemoration of Giovanni ordered by his sons. In establishing this identification, evidence is presented that suggests that Brunelleschi's supposed disapproval of Donatello's work in the sacristy arose less from problems of stylistic incompatibility than from the position of the sacristy as a monument caught between two generations of Medici with differing conceptions of Giovanni's commemoration.