Marino Sanudo, called Torsello, was a merchant, chronicler, historian, lobbyist, and crusade theorist and propagandist.
Sanudo was born about 1270 into a distinguished Venetian family, one branch of which ruled the island of Naxos in the Aegean Sea. After extensive experience of the eastern Mediterranean as a young man, Sanudo composed the Con- ditiones Terrae Sanctae (1306-1309), a scheme for an economic blockade of Egypt as a preliminary to military action against the Mamlûk sultanate. Refining and expanding his ideas, Sanudo produced the Liber Secretorum (or Secreta) Fidelium Crucis, presented to Pope John XXII in 1321. Its first book contained a revamped Conditiones; the second dealt with the preliminary military assault on Egypt by a professional force, to be followed by a general crusade (Lat. passagium generale); the third included a history of Outremer to the early fourteenth century, in its final version relying on William of Tyre, James of Vitry, Vincent of Beauvais, and Het‘um the Armenian, as well as on original material, to which was appended a geographical description of the Holy Land and a summary of how a renewed kingdom of Jerusalem should be organized.
Although set within an overtly pious and revivalist frame, the Secreta constituted operational advice, not an appeal for action. Despite its apparent pragmatism, certain details remained contestably practical. With Sanudo’s manuscripts, produced in his Venetian atelier, came detailed maps, some designed by the Genoese cartographer Pietro Vesconte. At least nineteen manuscripts of the Secreta survive.
To press his ideas, Sanudo exhaustively visited or corresponded with the courts of rulers interested in reviving the holy war in the East. Earlier than many in the West, Sanudo appreciated the danger posed by Turkish emirates in the Aegean, warnings that contributed to the anti-Turkish league of 1332-1334. Sanudo also wrote a continuation of the chronicle of Geoffrey of Villehardouin and an Istoria del Regno di Romania (1328-1333).