Marco Sanudo was a Lord of Gridia (a fief in Andros).Mihail-Dimitri Sturdza, Dictionnaire Historique et Généalogique des Grandes Familles de Grèce, d'Albanie et de Constantinople, Paris: Sturdza, 1983, p. 549
Ancestry He was the son of Marco II Sanudo, third Duke of the Archipelago, and the brother of William I Sanudo, fourth Duke of the Archipelago.
Marriage and issue He married ... and had Guglielmazzo Sanudo, Lord of Gridia.
References
Ancestry of Sultana Nur-Banu (Cecilia Venier-Baffo)