The Battle of Campaldino was a battle between the Guelphs and Ghibellines on 11 June 1289. Mixed bands of pro-papal Guelf forces of Florence and allies, Pistoia, Lucca, Siena and Prato, all loosely commanded by the paid condottiero Amerigo di Narbona with his own professional following, met a Ghibelline force from Arezzo including the perhaps reluctant bishop, Guglielmino degli Ubertini, in the plain of Campaldino, which leads from Pratovecchio to Poppi, part of the Tuscan countryside along the upper Arno called the Casentino.