These two possible inspirations, the Tomb of Constantine and the Florentine Baptistery, roughly correspond to poles of private and public association. The linkage to the tomb of Constantine on the one hand suggests that the Medici at this point already (and perhaps audaciously) conceived of themselves, the oligopolists turned oligarchs they were quickly becoming, on the model of the famous Christian Emperor, occupying a position of political leadership integrally tied to, indeed bulwarking, the authority of the Church. And whether or not the connection to the tomb of Constantine is to be believed, the all’antica classification remains valid, with all its attendant splendor. On the other hand, the correspondence with the Florentine Baptistery, connecting one family’s domicile for their dead to one of the Florence’s most potent emblems, suggests the dovetailing of one family’s private glories with the honor of the city. Whatever might be thought of the relatively esoteric connection to the tomb of Constantine, the emulation of the Florentine Baptistery, of a feature, the tholos lantern, unique to it, is all but undeniable.
The connection to the Florentine Baptistry is echoed in another of the Sacristy’s features, its bronze doors flanking the sacrasella and designed by Donatello (fig. 7, 8). This was a curious choice: an anomaly within a private chapel, the novelty was noted by contemporary Filarete in his account, who otherwise pays no mind to Donatello’s other work, the stucco reliefs over the aedicule and along the dome, for the Sacristy. Where rich bronze doors like these, with figurated relief work, were typically situated in Quattrocento Florence were public spaces, not private chapels – to name only the most poignant example, Ghiberti’s doors for the Florentine Baptistery.
The iconography of Donatello’s doors mirrors the marriage of private and public suggested by their very presence within the chapel. The door to the left of the sacresella is known simply as the Martyr’s Door due to its figures all holding palm branches, traditional symbols of martyrdom. Only the identity of four amongst them is discernible: St. Stephen with stone in the crown of his head, St. Lawrence with gridiron, and Sts. Cosmas and Damian with their small medicine boxes. Like the thematic cycle of the St. John along the tondi, the ranks of martyrs and elect would have been appropriate subjects for a funerary chapel, and the Sts. Cosmas and Damian not only invoked the Medici family by way of patronymic (they were the medici, or doctor saints), but served as surrogate saints for Cosimo and Lorenzo Medici, who by this point had taken over the decoration of the Sacristy following their father, Giovanni’s death.
It is the other door, however, to the right of the sacrasella, the so-called “Apostle’s Door,” and its uppermost two panels that belies the contemporary circumstances motivating the Sacristy’s decorative program. To the left are St. John the Baptist and St. John the Evangelist (fig. 9). This was an unusual pairing: John the Baptist had never made an appearance in any Medici imagery until now, but his introduction, and concurrently, the implications of Florence’s own patron saint, conjoined with the Medici’s patron saint is clear enough. To the right of the two Johns, are Sts. Peter and Paul, traditional symbols of the papacy (fig. 9).
 Howard Saalman, Filippo Brunelleschi: The Buildings (University Park, PA: Pennsylvania State UP, 1993), 123.
 For another interpretation of the Old Sacristy, as it relates to Cosimo’s impressive body of Hermetic knowledge see Gabirel Blumenthanl, “Science of the Magi: The Old Sacristy of San Lorenz and The Medici,” Notes in the History of Art 6, no. 1 (Fall 1986): 1-11.
 Ibid., 128, 140.
 John T Paoletti,"Donatello's Bronze Doors for the Old Sacristy of San Lorenzo," Artibus Et Historiae 11, no. 21 (1990): 58.
 Ibid., 53, 58.
 Ibid., 44
 Ibid., 61
 Patricia Fortini Brown, "Laetentur Caeli: The Council of Florence and the Astronomical Fresco in the Old Sacristy," Journal of the Warburg and Courtauld Institutes 44 (1981): 180.