San Gallo Gate, Medieval city gate in Piazza della Libertà, Florence, Italy.

San Gallo Gate stands in Piazza della Libertà, facing the Triumphal Arch, on the northern edge of Florence. It is a stone city gate with a central passage and is decorated on the outside with two stone Marzocco lions, the emblem of the Guelph party. Inside, the lunette preserves traces of a fresco of the Madonna and saints.

Work on the gate began in 1284 under Arnolfo di Cambio and was finished in 1327, opening the northern road toward Bologna. It was part of a ring of walls that enclosed the city during the medieval period.

The gate's name comes from the convent of San Gallo that once stood just outside it. Two stone Marzocco lions, the emblem of the Guelph Party, decorate the exterior, while the inner lunette keeps traces of a fresco of the Madonna and saints. An inscription records the 1708 passage of King Frederick IV of Denmark, who came to Florence for Caterina de' Pazzi, a girl he had loved as a prince but who had by then taken vows.

The gate sits at the northern edge of the old city and is easy to reach on foot from the historic center. From here, a walk along the surviving sections of the old city walls gives a good sense of how the fortifications once surrounded Florence.

The architect Giuliano Giamberti took the nickname "da Sangallo" from the convent of San Gallo just outside this gate, which he designed; the road did not name him. That convent was demolished before the siege of Florence to clear the field of fire for cannon on the walls. Boccaccio set Calandrino's search for the heliotrope in the Mugnone's pebbly bed, which served as the gate's moat.