The current province of Gelderland covers about the area of three quarters of the historical Duchy of Guelders, that arose out of the Frankish pagus Hamaland. Guelders was a county in the late 11th century and then a duchy in the Holy Roman Empire, including parts of the present-day Dutch province of Limburg and the German district of Kleve (Cleves). Geldern, the original seat of the dukes, today is in Kleve, Germany. In 1543, Gelderland became one of the Seventeen Provinces of the Habsburg Netherlands, though not one of the richer or more densely populated provinces. During World War II, it saw heavy fighting between Allied Paratroopers, British XXX Corps and the German II SS Panzer Corps, also known as the Battle of Arnhem.