Venetian Gothic architecture influenced by Byzantine architecture
Islamic and Byzantine influence
The influence of Islamic architecture is reflected in some features of the Venetian style, in particular the use of colour and pattern on outside walls, and sometimes stone grills on windows, and perhaps purely decorative crenellations on rooflines.  During the period the Venetian economy was heavily bound up with trade with both the Islamic world and the Byzantine Empire, and the architectural styles of these two are somewhat entangled, especially in the early Islamic period.As an example, decorating walls with large veneers of fancy coloured marble or other stones, which was certainly a Venetian taste, was also found in Byzantine and Islamic architecture, but both had derived it from imperial Roman architecture.  There are still examples in Ravenna (ruled by Venice from 1440 to 1509), Milan as well as Rome, and very likely much of the stripping of these from other surviving Roman buildings had not yet taken place.
Venetians may also have regarded some aspects of Byzantine and Islamic architecture as reflecting the world of Early Christianity – all over Italy "eastern" costume very often served for biblical figures in art, and the paintings of some Venetians, for example St Mark Preaching at Alexandria by Gentile Bellini (c. 1505) also use clearly Islamic architecture (including stone grills), although also reflecting the Byzantine styles of Constantinople, which Bellini visited in 1479, only some twenty-five years after it became the Ottoman capital.  There were also Venetian connections with Islamic styles though Sicily and southern Italy, and possibly al-Andalus (Islamic Spain).  Venetians probably saw the eastern elements in their architecture in a complex way, reflecting and celebrating both their history and the cause of their trade-derived wealth.Venetian traders, and those of rival cities, reached into Persia and Central Asia in the Pax Mongolica after the Mongol conquests, from roughly 1240 to 1360.   There were small Venetian colonies of merchants in Alexandria, as well as Constantinople.  Venice's relations with the Byzantine Empire were still more intimate and complicated, involving many wars, treaties, and massacres.