The Dominican monastery of San Marco was founded in 1436. Built on the site of a 12th-century Vallombrosan monastery, it is an impressive architectural complex designed by the architect Michelozzo. San Marco played a central role in the religious, cultural and political life of the city in the Quattrocento, as is illustrated by the story of the Dominican friar Girolamo Savonarola of Ferrara, who had close associations with the monastery, but was executed in the Piazza della Signoria on 23 May 1498 for his calls for a radical reform of the Church. The church is decorated with frescoes by some of the greatest artists of the 15th century, among them Fra Angelico and Fra Bartolomeo. In 1869 the ex-convent was transformed into the Museo Nazionale di San Marco.
On the first floor is the monastery’s celebrated Biblioteca, considered to be the first public library in Europe. Commissioned by Cosimo the Elder (1437-1444), it consists of an elegant hall divided into three naves originally painted blue-green, lined with bookshelves, and furnished with 64 wooden benches. The library contains valuable manuscripts that belonged to the Medici family, to Pico della Mirandola, and to Poliziano. Leonardo mentions this library in the Codex Atlanticus (toward 1480) and in the Codex Arundel (ca. 1505).