Bad Saulgau is a town in the district of Sigmaringen, in Baden-Württemberg, Germany. It is situated 23 km east of Sigmaringen, and 27 km north of Ravensburg between the Danube and Lake Constance. The location was already a Celtic settlement and owes its name to the spring goddess Sulis. The first historical reference to the settlement dates back to 819. In 1239, the town was acknowledged by Frederick II, Holy Roman Emperor. It became a possession of the House of Habsburg in 1299, and thus part of the Holy Roman Empire.