By the last decades of the ninth/fifteenth century an interest in representing the “real” world in religious narratives set within an authentic biblical background prompted Venetian artists to integrate the Mamluk world into their paintings. At that time, the Mamluks had control over Jerusalem, as well as Alexandria (Egypt), where Saint Mark had introduced Christianity. The Republic’s strong commercial ties and diplomatic relations with the Mamluk Sultanate provided Venetian painters with the necessary Mamluk details. The present article reflects on one of the most celebrated paintings in the San Marco cycle, St. Mark Preaching in Alexandria by Gentile Bellini. In an attempt to figure out why the artist incorporated an Ottoman wearing a sword among hoards of Mamluk male and female characters as they would have appeared at that time in Alexandria, this paper identifies Mamluk costume in some detail. The purpose of this study is to explain the allusions Gentile’s painting contained to contemporary events. In order to accomplish its purpose, the study examines the Mamluk phenomenon in Venetian painting, assesses Gentile’s Alexandrian setting and his accuracy in portraying Mamluk versus Ottoman figures, analyzes the relations between the Republic and the world of Islam, and finally discusses Venice’s interest in the Mamluk world.