The Republic of Pisa is a de facto independent state centered on the Tuscan city of Pisa during the late tenth and eleventh centuries.

It rises to become an economic powerhouse, a commercial center whose merchants dominate Mediterranean and Italian trade for a century before being surpassed and superseded by Genoa.

The power of Pisa as a mighty maritime nation begins to grow and reaches its apex in the 11th century when it acquires traditional fame as one of the four main historical Maritime Republics of Italy.