The main gate (Porta Maestra) was built in the 14th or 15th century after the construction of the city walls, which began in the 13th century, was completed. Because a palm tree grew nearby, it has also been referred to as Palm Gate (Porta del datallo) since the 15th century. For the same reason it has been called Market Gate (Porta del mercato) since the 16th century after the market place in front of the gate.