structural:summarization, structural:scholar_edition
The Republic of Siena was a historic state consisting of the city of Siena and its surrounding territory in Tuscany, central Italy. It existed for over 400 years, from 1125 to 1555. During its existence, it gradually expanded throughout southern Tuscany becoming one of the major economic powers of the Middle Ages, and one of the most important commercial, financial and artistic centers in Europe. From 1287 to 1355, during the rule of the Noveschi, the Republic experienced a period of great political and economic splendor: new buildings were commissioned, including that of the Cathedral of Siena, the Palazzo Pubblico, and a substantial part of the city walls completed. This government is in fact defined by historians as the "good governance". A combination of economic decline, sparked by the Black Death, and political instability led to its absorption by the rival Duchy of Florence during the Italian War of 1551–1559. Despite resisting for 18 months, it surrendered on 21 April 1555, marking the end of the republic.