Belfort Montbéliard, who granted it a charter in 1307. Previously an Austrian possession, Belfort was transferred to France by the Treaty of Westphalia (1648), which ended the Thirty Years' War. The town's fortifications were extended and developed by the military architect Vauban for Louis XIV. Until 1871, Belfort was part of the "département" of Haut-Rhin, in Alsace. The Siege of Belfort (between 3 November 1870 and 18 February 1871) was successfully resisted until the garrison was ordered to surrender 21 days after the armistice between France and Prussia. The region was not annexed by Prussia like the rest of Alsace and
War of the Spanish Succession was reliant on the so-called "Maritime Powers" (England and the Dutch Republic) and also a higher priority for them. By formalising religious divisions within the Empire, the [[Peace of Westphalia|1648 Peace of Westphalia]] weakened its integrity and by 1700, the larger German states were pursuing their own policies. [[Electorate of Bavaria|Bavaria]] allied itself with France while as King of Poland, [[Augustus II the Strong|Augustus of Saxony]] was fully occupied by the [[Great Northern War]]. To gain [[Frederick I of Prussia|Frederick of Prussia]]'s support, Leopold recognised him as King, with Prussia made an equal member of the Grand Alliance. [[George I