It was also an associate and ally of the Swiss Confederation and played a role in the buildup to the Thirty Years' War.

In the late twelfth century, the communities in the valleys in Raetia were generally small and independent.

For years blood feuds and battles had raged between the Lords of Belmont, Werdenberg, Rhäzüns and the Bishop of Chur as well as minor nobles.

To reduce the violence and encourage trade, the leaders and nobles of the valleys proposed forming a league or alliance.

The Grey League was founded through the alliance of 21 communities from the Vorderrhein and Hinterrhein valleys in the Alps.

Landfrieden was the first step from arbitrary punishments handed out by the injured party to a modern penal system.

[3] On April 4, 1399, the ruler of Hohentrins (who was sworn to the Count of Werdenberg-Heiligenburg) and the people of Trin, Tamins and the toll bridge to Reichenau joined the League.

In 1424 the communities of the Hinterrhein valley, Heinzenberg-Thusis, Schams and Rheinwald, fully joined the League.

The Musso war against the Duchy of Milan in 1520 pushed the League closer to the Swiss Confederacy.