Pisa

   Italian maritime republic in Tuscany on the Arno River. Byzantium (q.v.) used Pisa, like Genoa (q.v.), as a counterweight to the rising commercial power of Venice (q.v.). In 1111 Alexios I Komnenos (q.v.) extended Pisa trading privileges that included trading quarters along the Golden Horn (q.v.). Privileges were renewed in 1136 by John II (q.v.), lost in 1163, and restored in 1170 by Manuel I. The Pisans suffered in the general slaughter of Latins in Constantinople (q.v.) in 1182. Nevertheless, their privileges were again renewed in 1192 by Isaac II (q.v.), partly because some Genoese had taken to piracy in Byzantine waters. The conquest ofConstantinople by the Fourth Crusade (qq.v.) in 1204 was a triumph for Venice and a setback for Pisa and Genoa. Pisa never fully recovered its commercial position in Byzantium, and in 1439 its privileges were given to Florence (q.v.).