House of Visconti
The Gherardeschi had a rivalry with the House of Visconti, another Ghibelline family of Pisa. In 1237, the Archbishop and the Emperor Frederick II intervened in Pisa to reconcile the two rivals, but failed. In 1254, the citizenry rebelled and imposed twelve "Anziani del Popolo" ("Elders of the People") as their political representatives.