Isaac‘s contract with Emperor Maximilian I., 1497. Innsbruck, Tiroler Landesarchiv (A-Ila), Urkunden-Nr. 5147.
Innsbruck, Tiroler Landesarchiv, Urkunden-Nr. I 5147/2: Henricus Isaac’s contract with Maximilian I. (1497). » I. Kap. Maximilian’s chapels in Austria.