The large Palazzo Medici in Florence, built by Cosimo, was designed by him; it is one of the noblest specimens of Italian fifteenth-century architecture, in which the great taste and skill of the architect has combined the delicate lightness of the earlier Italian Gothic with the massive stateliness of the classical style. With great engineering skill Michelozzo shored up, and partly rebuilt, the Palazzo Vecchio, then in a ruinous condition, and added to it many important rooms and staircases. When, in 1437, through Cosimo's liberality, the monastery of San Marco at Florence was handed over to the Dominicans of Fiesole, Michelozzo was employed to rebuild the domestic part and remodel the church. For Cosimo he designed numerous other buildings, most of them of noteworthy importance. Among these were a guest-house at Jerusalem for the use of Florentine pilgrims, Cosimo's summer villa at Careggi, and the fortified "castello" that he rebuilt from 1452 as the Villa Medicea di Cafaggiolo in Mugello. For Giovanni de' Medici, Cosimo's son, he also built a very large villa at Fiesole. Between 1445 and 1451, he also expanded Villa San Girolamo next to Villa Medici at the behest of Cosimo.