 He based this theory on his own interpretation of Italian chronicles.The ""Dictionnaire historique et Généalogique des grandes familles de Grèce, d'Albanie et de Constantinople"" (1983) by Mihail-Dimitri Sturdza rejected the theory, based on the silence of Byzantine primary sources.Marco lost some of his islands to the Byzantine Empire early in his reign, but he recovered them two decades later, in time to leave the whole of the original duchy to his son William I.

Marco II had at least two known children.