apitulum Ianua sits just outside Zaragoza, on a small island where the Gállego river flows into the Ebro river. The island is not large, about 120 yards long by 30 yards wide in an elongated diamond shape, but it has room enough for several sancta and a large hall that hosts a Mercere Portal linking to Doissetep.

The portal is the reason for Iannua's existence, as it provides ready access to Zaragoza and Hispania for magi from Doissetep. Enchanted by magi Merceris in the early twelfth century, the portal soon became embroiled in controversy between Doissetep and conventa in Hispania. Persistent charges of interference by Doissetep in mundane affairs in Hispania resulted in repeated Quaesitorial investigations, and eventually resulted in Iannua becoming a de facto capitulum Quaestoricius.