lagoons. The archbishop himself took refuge in Grado, where he was claimed as patriarch, during the schism of the Three Chapters. At the end of the invasion, many of the ancient dioceses of the mainland were restored by the Lombards, while the exiles supported the new sees in the lagoons. Two patriarchs emerged: the Patriarchate of Old Aquileia on the mainland and Patriarchate of Grado. In 774 or 775, Pope Adrian I and John IV, Patriarch of Grado, authorized the establishment of an episcopal see on the island of Olivolo. The first bishop, Obelerius, was nominated, invested and enthroned by the doge and consecrated by the patriarch. The Bishop of Olivolo was subordinate to Grado and had jurisdiction over the islands of Olivolo, Rialto, Luprio, Gemini, Scopulo or Dorsoduro, Spinalonga, Biria and other minor islands of the central group. The diocese's cathedral was San Pietro di Castello. In 828 the body of Saint Mark the Evangelist was smuggled from Alexandria, Egypt, to Venice. When the ship reached Olivolo island in Venice, the saint made signs (or so it was claimed) showing he did not want to be placed in the custody of the bishop. Instead, he was taken to the doge's chapel, and planning began to create a magnificent new temple, St Mark's Basilica, suitable for such important relics. The legend that St. Mark himself had preached the Gospel at Venice grew up in later times. In 1074, the Bishop of Olivolo began to be styled the Bishop of Castello. Enrico Contarini was the first to hold this title. In 1084 the Emperor Alexios I Komnenos in his Golden Bull recognized the full independence of Venice, along with freedom from tributes, trade restrictions and customs duties. The Republic of Venice began its Golden Age under the Doge Enrico Dandolo (1192–1205). Under him the French Crusading army of the Fourth Crusade was used to bring Trieste and Zara under Venetian sway, and then to obtain a large part of the Latin Empire of Constantinople along the east coast of the Adriatic, most of the Peloponnesus and settlements in the Sea of Marmora, the Black Sea and the Aegean. The relationship between the bishop, the patriarch and the doge was complex. The bishops of Olivolo, and then Castello, were technically suffragans of the Patriarch of Grado. In practice they maintained independence. From the middle of the 11th century the patriarchs took up