 In 1442, Frederick allied himself with Rudolf Stüssi, burgomaster of Zurich, against the Old Swiss Confederacy in the Old Zurich War (Alter Zürichkrieg) but lost.In 1448, he entered into the Concordat of Vienna with the Holy See, which remained in force until 1806 and regulated the relationship between the Habsburgs and the Holy See.In 1452, at the age of 37, Frederick III travelled to Italy to receive his bride and to be crowned Holy Roman Emperor.