Porta Santo Stefano, so called the “Gate to Tuscany” (“Porta per la Toscana”), was built in the 13th century, many times rebuilt and restored during the last two centuries. Its fortification was reinforced in the 15th century. It was heavily damaged by artillery during the siege in 1512 when the original tower was destroyed. The gate was rebuilt with a new keep one year later. The previous buildings were demolished in 1843 and two still existing houses were built on their place – they mark the monumental entrance into the town called “Gregorian barrier” (“barriera gregoriana”). Due to the transformation of the main road from Florence, the gate has become the main exchange point for the traffic and merchandise between Bologna and Florence.