
Grosseto is a city in the central Italian region of Tuscany. Grosseto grew in importance as the influence of other Tuscan city-states declined during the 12th century, and it acquired the Bishopric of Roselle in 1138. In 1151, its citizens swore loyalty to Siena; in 1222, the city revolted and formed its own government, only to be reconquered in 1244. In 1266 and 1355, the city again tried to rebel against Sienese rule, and it found itself occupied, ravaged, excommunicated by Pope Clement IV, freed in a republic, besieged by Emperor Louis IV of Germany and by the Antipope Nicholas V in 1328, until it submitted to Siena. In 1559, Emperor Charles V had Grosseto handed over to the Grand Duchy of Tuscany, and it remained a part of Tuscany until the reunification of Italy in 1860. In 2016, Grosseto had a population of 82,131 people.