English: Venetian possessions (in green) of the Ionian Sea area in the 18th century. After the Treaty of Passarowitz (1718), the Venetian seaborne empire outside the Adriatic was reduced to the Ionian Islands (including Cerigo off the Peloponnesus) and three precarious beachheads on the continent: Butrinto, Preveza and Vonitsa. Cropped from a map of Italy and surrounding area published by Homann Heirs in 1742.