The Grey League (, , or ), sometimes called Oberbund, formed in 1395 in the Vorderrhein and Hinterrhein valleys, Raetia. The name Grey League is derived from the homespun grey clothes worn by the people. The league became part of the canton of Graubünden. The Grey League allied itself to the two other powers of Raetia in 1471, forming the Three Leagues. It was also an associate and ally of the Swiss Confederation and played a role in the build up to the Thirty Years' War.