Treaty of San Germano

The Treaty of San Germano was signed on 20 July 1230 at San Germano, present-day Cassino, between Holy Roman Emperor Frederick II and Pope Gregory IX. A Dominican, Guala de Roniis, was responsible for the negotiations.

Negotiations for the treaty were proposed by the Teutonic grand master Hermann von Salza and opened at Aquino in November 1229. The papal negotiators were Tommaso da Capua and Jean Halgrin.

After the treaty was signed, Guala became the bishop of Brescia. Based on the terms of the agreement, Frederick's forces ceased to occupy portions of the Pontifical States. Moreover, all papal possessions in Sicily were restored to the Pope.