The earliest mention of a church dedicated to St. Francis is in 1233. The Pisan community of Lesser Friars expanded rapidly, aided by support from the city and private donations. The Church became an important meeting place for the public, the seat of a studium, with a library and a scriptorium.In 1261, in recognition of the important role of the friar preachers, Archbishop Visconti inaugurated the extension to the Church under the guidance of Giovanni di Simone. The belfry, daringly supported by a flying arch, is particularly interesting. Financial problems, connected to wars at the end of the 13th century, put a halt to building.