The Tuscan League's members (originally the communes of Lucca, Florence and Sienna, Vienna, the people living under the castles of Prato and San Miniato, and the bishoric of Volterra) swore not to make any alliances without papal approval.
The Tuscan League, also known as the League of San Genesio, was formed on 11 November 1197 at by the chief cities, barons and bishops of the Duchy of Tuscany shortly after the death of the Emperor Henry VI (27 September). The original signatories were the communes of Lucca, Florence and Siena, the people living under the castles of Prato and San Miniato, and the bishopric of Volterra. Its members swore not to make any alliances without papal approval, nor to make any peace or truce "with any emperor, king, prince, duke or margrave" without the approval of the rectors of the league. 
