The church of St. Sisto was built in Cortevecchia in 1087, soon after the Pisan conquest of the Al Mahdiya emporium inTunisia. Here, the military victories of the Pisan Republic are celebrated, on a date when many of them occurred, 6th August, in honour of the Saint. The name Cortevecchia reminds us that in the early middle ages the political heart of Pisa was here, where the Longobard King’s Steward resided.

In spite of several renovations (in mid 15th century, early 17th century and in the 1760s), the church has changed very little in appearance since the middle ages. The façade, divided into three parts, is outlined by a decoration of dead archlets and ceramic basins mostly imported from the western Mediterranean; below there are three doors and a recently inserted double mullioned window. The left outer wall is intact, built from small limestone blocks and decorated along the top in the same way as the front. The interior is divided into three aisles by two rows of pillars in granite and grey marble, crowned by capitals, some of which came from ancient buildings and were re-used in the church. Two fragments from boats - a rudder and a mast (14th – 15th centuries) – lean against the inner wall of the facade, a reminder of the part played by the Church under the patronage of the Pisan Comune. The civic function of this church is highlighted by the standards of the four quarters of Pisa in this part of the Church. 

The bell tower, behind the Church, is built of bricks on a base of stone blocks and is decorated with dead archlets and ceramic basins and a pointed roof.