382 eighteen The Laurentian Library Patronage and Building History Silvia Catitti In January 1524 a reluctant 1 Michelangelo received from Pope Clement VII de’ Medici (1523–34) the commission to build a library within the mid-fifteenth- century canonry of San Lorenzo (Fig. 18.1). From the time in which it was under construction up to the present day, the building has been considered one of the most significant examples of Renaissance architec- ture. It was the first monumental space of the modern era to be built anew as a secular library accessible to the pub- lic. 2 For Michelangelo, it was the first building he designed without having to conform to an existing spatial model. For Clement VII, it was his first architectural commission inde- pendent from his cousin, Pope Leo X. Due to exceptional circumstances, it is one of the best documented architectural commissions of the Renaissance. The complex of San Lorenzo hosted the lodgings of the canons, who were responsible for the administration, lit- urgy, and maintenance of the fabrica of the basilica designed by Brunelleschi. The library, which appears as an additional story superimposed above the west wing of the canonry, con- sists of an elongated open space accessible through a vertical- izing vestibule (Figs. 18.2–18.3). From 1524 until the Sack of Rome, in 1527, Michelangelo worked incessantly on the library. Owing to his Republican sentiments, his collaboration with the pontiff began to fade around the time of the Siege of Florence (1529–30), when his patron became a political and military enemy. In the tur- bulent days that followed the fall of the Republic, the artist even went into hiding in a recess of the library roof. 3 After the victory of the papal troops, Clement VII was passionately concerned that his plan of public magnificence should come to fruition. He reinstated Michelangelo, who returned to work in the summer of 1533. Nevertheless, after supervising the installation of a few architectural elements of the library, the artist left Florence for Rome in 1534, never to return. The same year, the pope died. Like nearly all buildings designed by Michelangelo, the library project was not only constrained by a preexisting structure, but it remained unfinished 4 and was eventually completed by others. In part, the artist was overwhelmed with too many weighty commissions, and he was notori- ously reluctant to delegate. 5 Nonetheless, the reading room and vestibule of the library today adhere more closely to Michelangelo’s ideas than any other building he designed. Indeed, he was able to supervise the building site for a longer period of time 6 and, most notably, unlike in other cases, he left some clues to his intentions, so that subsequent artists were able to develop his general indications. In a different phase of the relation between the Medici and the city, Duke Cosimo I took on the role of the new patron of the unfinished library. Cosimo included the completion of the building within a broader program, which encompassed several architectural works in Florence, with the aim of cel- ebrating his own role as an enlightened promoter of the arts and letters. 7 After he became duke (1537), Cosimo sponsored the completion of the architecture and the furnishing of the reading room, as well as the installation of the staircase in the vestibule. The stairs, for which Michelangelo had provided contradictory instructions over the years, proved to be a chal- lenging task. 8 To a modern observer, it might appear surprising