The new freedom did not last long; 15 years of battles and sieges by the Florentine troops led by Antonio da Filicaja, Averardo Salviati and Niccolò Capponi were made, but they failed to conquer the city. Vitellozzo Vitelli with his brother Paolo were the only ones who actually managed to break the strong defences of Pisa and make a breach in the Stampace bastion in the southern west part of the walls, but he did not enter the city. For that, they were suspected of treachery and Paolo was put to death. However, the resources of Pisa were getting low, and at the end, the city was sold to the Visconti family from Milan and eventually to Florence again. Its role of major port of Tuscany went to Livorno. Pisa acquired a mainly cultural role spurred by the presence of the University of Pisa, created in 1343, and later reinforced by the Scuola Normale Superiore di Pisa (1810) and Sant'Anna School of Advanced Studies (1987).