Treaty of Compiègne (1635)

The Treaty of Compiègne, signed on 30 April 1635 Old Style, was a mutual defence alliance between France and Sweden.

Prior to 1635, France provided indirect diplomatic and financial support to opponents of their Habsburg rivals in Spain and the Holy Roman Empire, but avoided direct involvement. This included backing the Dutch Republic in the Eighty Years' War with Spain, and Swedish intervention in the Thirty Years War.

After the Swedes and their German allies were defeated at Nördlingen in September 1634, France decided to enter the war. Under the treaty, they agreed to continue subsidising Swedish participation, and declare war on Spain, beginning the Franco-Spanish War (1635–1659).