The county was first mentioned in about 1096, when Gerard III of Wassenberg was first documented as "Count of Guelders". It was then in the territory of Lower Lorraine, in the area of Geldern and Roermond. Its main stronghold was at Montfort (built 1260). Count Gerard's son Gerard II in 1127 got the County of Zutphen in northern Hamaland by marriage. In the 12th and 13th century, Guelders became larger very quickly downstream along the sides of the Maas, Rhine, and IJssel rivers. It even claimed the lands in the Duchy of Limburg. In 1288, it lost the Battle of Worringen against Berg and Brabant.