Severus was the last Patriarch of Aquileia with seat in Grado, from 586 to his death in 606.
Venice had its own church organisation from the 800s, but the origins go back to before the Lombard invasion, and events in the Eastern Roman Empire.
The complete list of the Patriarchs of Grade, Patriarchs of Grado in Venice, and Patriarchs of Venice, since 717 until today