Due to the barbarian incursions of the 5th century, the people of Aquileia fled and took refuge along the coast making Grado their New Aquileia, which also inherited the ancient episcopal seat. Grado remained under the Greek-Byzantine sphere of influence, and the two important basilicas of the 5th - 6th century still bear witness to that period; the oldest one is devoted to Santa Maria delle Grazie, the other one is devoted to Santa Eufemia, martyr at the age of sixteen in Chalcedonia on the Black Sea. After Jerusalem, Constantinople, Rome, Alexandria and Antiochia also the Bishop of Grado was invested with the title of Patriarch, a title which would be reclaimed by Aquileia after the bishop's death (565) and the arrival of Alboin 3 years later. Still today, we don't know the number of churches and monasteries scattered along the coastal area, which around the year one thousand turned into the lagoon. It is in this period that the Patriarch of Grado moved to Venice, where he almost permanently stayed until the Patriarchate was definitively transferred in 1451.