hospital and few palaces. All the complex is kept by the Opera (fabrica ecclesiae) della Primaziale Pisana, an old non profit foundation that operates since the building of the Cathedral (1063) to the maintenance of the sacred buildings. The area is framed by medieval walls kept by municipality administration. Other sights include: Knights' Square (), where the , with its impressive façade designed by Giorgio Vasari may be seen. Sited on the square Santo Stefano dei Cavalieri, church sited on Piazza dei Cavalieri, and also designed by Vasari. It had originally a single nave; two more were added in the 17th century. It houses a bust by Donatello, and paintings by Vasari, Jacopo Ligozzi, Alessandro Fei, and Pontormo. It also contains spoils from the many naval battles between the Cavalieri (Knights of St. Stephan) and the Turks between the 16th and 18th centuries, including the Turkish battle pennant hoisted from Ali Pacha's flagship at the 1571 Battle of Lepanto. St. Sixtus. This small church, consecrated in 1133, is also close to the Piazza dei Cavalieri. It was used as a seat of the most important notarial deeds of the town, also hosting the Council of Elders. It is today one of the best preserved early Romanesque buildings in town. St. Francis. The church of San Francesco may have been designed by Giovanni di Simone, built after 1276. In 1343 new chapels were added and the church was elevated. It has a single nave and a notable belfry, as well as a 15th-century cloister. It houses works by Jacopo da Empoli, Taddeo Gaddi and Santi di Tito. In the Gherardesca Chapel are buried Ugolino della Gherardesca and his sons. San Frediano. This church, built by 1061, has a basilica interior with three aisles, with a crucifix from the 12th century. Paintings from the 16th century were added during a restoration, including works by Ventura Salimbeni, Domenico Passignano, Aurelio Lomi, and Rutilio Manetti. San Nicola. This medieval church built by 1097, was enlarged between 1297 and 1313 by the Augustinians, perhaps by the design of Giovanni Pisano. The octagonal belfry is from the second half of the 13th century. The paintings include the Madonna with Child by Francesco Traini (14th century) and St. Nicholas Saving Pisa from the Plague (15th century). Noteworthy are also the wood sculptures by Giovanni and Nino Pisano, and the Annunciation by Francesco di Valdambrino. Santa Maria della