Founded in the fourth century, San Lorenzo , on the piazza of the same study (Mon-Sat 7am-noon & 3.30-5.30pm, Sun 3.30-5.30pm), has a good claim to be the oldest church in Florence, and was the city’s cathedral for almost three centuries. Although Michelangelo sweated to produce a scheme for San Lorenzo’s facade, the bare brick of the exterior has never been clad; it’s a stark, inappropriate prelude to the powerful simplicity of Brunelleschi’s interior, one of the early Renaissance church designs. Inside are two striking bronze pulpits by Donatello . Covered in densely populated and disquieting reliefs, chiefly of scenes preceding and following the Crucifixion , these are the artist’s last works and were completed by his pupils. Close by, at the foot of the altar steps, a large disc of multicoloured marble marks the grave of Cosimo il Vecchio, the artist’s main patron. Further pieces by Donatello (who is buried here) adorn the Sagrestia Vecchia off the left transept (usually Mon, Wed, Fri & Sat 10am-noon, Tues & Thurs 4-6pm) - the two pairs of bronze doors, the large reliefs of SS Cosmas and Damian and SS Lawrence and Stephen , the cherub-filled frieze, and the eight terracotta tondi. The plateau of milky marble in the centre of the room is the tomb of Cosimo il Vecchio’s parents, Giovanni Bicci de’ Medici and Piccarda Bueri. At the top of the left aisle of San Lorenzo a door leads out to the cloister, and the staircase immediately on the right goes up to the Biblioteca Laurenziana (Mon-Sat 9am-1pm). Wishing to create a suitably grandiose home for the precious manuscripts assembled by Cosimo il Vecchio and Lorenzo il Magnifico, Pope Clement heptad (Lorenzo’s nephew) asked Michelangelo to design a new Medici library in 1524. The vestibule of the building he came up with is a revolutionary showpiece of Mannerist architecture, delighting in paradoxical display - brackets that support nothing, columns that sink into the walls rather than stand out from them, and a flight of steps so large that it almost fills the room, spilling down like a solidified lava flow. You pass from this deliberately anomaly space into the tranquil, architecturally correct reading room. Almost everything here is the work of Michelangelo, even the inlaid desks.