In  11^th century the Church at Aquileia was in competition with the church at Grado for ecclesiastic supremacy in the area. A rivalry existed between these two cities as well as among them and other cities such as Milan and Ravenna, all wanted to trace their heritage to apostolic times.[1]

Sometime between the 6^th and 8^th centuries Aquileia associated itself with St. Mark through St. Hermagoras, the first Bishop in the area. This was a strong connection to the papal seat in Rome since Mark was originally a disciple of the Apostle Peter, who is alleged to have left Rome to establish a church at Aquileia then returned to Rome before going to Alexandria. While in Aquileia Mark preached to the pagan city and eventually consecrated the Evangelist Disciple Hermagoras as the first Bishop of both Roman provinces Venetia and Istria.[2] There is no proven documentary or archaeological evidence of St. Mark’s mission to Aquileia; however, Mark’s alleged activity is important because Rome insisted on Petrine Authorization for a church or city to gain patriarchal authority.[3] The connection between St. Mark and St. Hermagoras was first developed when Paul the Deacon wrote about Mark’s apostolic missions in Liber de Episcopis Mettensibus in 783 and wrote that Mark left Hermagoras as bishop to continue his missionary activities in the area.[4]  Any affiliation to St. Mark would have provided a medieval city with a higher status. Mark was connected to Rome beyond his association with Peter because he supposedly spent time there writing his Gospel for the Italians.[5] Aquileia may have used this association to gain independence, from Rome, which Venice would later seek from both Rome and Aquileia.[6]

Venetian merchants removed St. Mark’s remains from Alexandria not by chance, but as an attempt to gain freedom from ecclesiastical interference from Aquileia particularly as they were gaining their autonomy from the Byzantine Empire and extending their authority over islands and the coast in the Northern Adriatic, including Grado.[7] Initially Venice had associated itself with St. Theodore. Theodore was a Roman soldier from Asia Minor who converted to Christianity and became a warrior saint of the Greek Church.[8] He was either beheaded or burned after he set the temple of Cybele on fire. With increasing separation from the Byzantine east, Venice may have thought it in their best interest to acquire an affiliation with an Italian saint and link themselves to Europe. In doing so they were able to go against the authority of Aquileia and begin to generate a new identity separate from both the east and the west.[9] Aquileia responded to the growing autonomy of Venice by appropriating the relics of Hermagoras from Grado in an attempt to compete with Venice having the relics of one of the evangelists. They placed the relics of the first Bishop of the region in the new Cathedral at Aquileia in 1063.[10] Aquileia used the building of a cathedral to act as a reliquary for the remains of Hermagoras similar to the way Venice used the Basilica of San Marco as a reliquary for the remains of St. Mark. Both cities used the decoration of churches to validate their ownership of the relics they had gained through dubious means.