The fall of Groningen also changed the balance of forces in the German county of East Friesland, where the Lutheran Count of East Frisia, Edzard II, was opposed by the Calvinist forces in Emden. The States-General now laid a garrison in Emden, forcing the Count to recognise them diplomatically in the Treaty of Delfzijl of 1595. This also gave the Republic a strategic interest in the Ems River valley, which was reinforced during the stadtholders' large offensive of 1597. Maurice first seized the fortress of Rheinberg, a strategic Rhine crossing, and subsequently Groenlo, Oldenzaal, and Enschede, before capturing the county of Lingen.