Porta Maestra is located on the west side of the sea fortification. It is impressive in its construction and follows the so-called Tuscan architectural style, approaching the aesthetics of the monumental gates of the cities. Constructed from grey limestone, it has on either side of the opening two semi-columns and a lintel, where the name of the General Provisioner of the Kingdom of Crete (Provisor Generalis Regni Cretae), Luca Michiel is carved under whose supervision the first phase of the construction of the Spinalonga fortress took place (1579-1584). The gate is the official entrance to the fortress of Spinalonga during the Venetian era and during the Ottoman and Leper colony eras.