The Duchy of the Archipelago, also known as Duchy of Naxos or Duchy of the Aegean, was a maritime state created by Venetian interests in the Cyclades archipelago in the Aegean Sea, in the aftermath of the Fourth Crusade, centered on the islands of Naxos and Paros. It included all the Cyclades. In 1537, it became a tributary of the Ottoman Empire, and was annexed by the Ottomans in 1579; however, Christian rule survived in islands such as Sifnos and Tinos.

The Fourth Crusade (1202–1204) was a Latin Christian armed expedition called by Pope Innocent III. The stated intent of the expedition was to recapture the Muslim-controlled city of Jerusalem, by first defeating the powerful Egyptian Ayyubid Sultanate. However, a sequence of economic and political events culminated in the Crusader army's 1202 siege of Zara and the 1204 sack of Constantinople, rather than the conquest of Egypt as originally planned. This led to the Partitio terrarum imperii Romaniae or the partition of the Byzantine Empire by the Crusaders and their Venetian allies leading to a period known as Frankokratia, or "Rule of the Franks" in Greek.