Chioggia and Sottomarina were not prominent in antiquity, although they are first mentioned in Pliny[1] as the fossa Clodia. Local legend attributes this name to its founding by a Clodius, but the origin of this belief is not known.

The name of the town has changed often, being Clodia, Cluza, Clugia, Chiozza, Chiozzo,[2] Chioggio,[2] and Chioggia.[3] The most ancient documents naming Chioggia date from the 6th century AD, when it was part of the Byzantine Empire. Chioggia was destroyed by King Pippin of Italy in the 9th century, but rebuilt around a new industry based on salt pans. In the Middle Ages, Chioggia proper was known as Clugia major, whereas Clugia minor was a sand bar about 600 m further into the Adriatic. A free commune and an episcopal see from 1110, it had later an important role in the so-called War of Chioggia between Genoa and Venice, being conquered by Genoa in 1378 and finally by Venice in June 1380. Although the town remained largely autonomous, it was always thereafter subordinate to Venice. On 14 March 1381, Chioggia concluded an alliance with Zadar and Trogir against Venice, and finally Chioggia became better protected by Venice in 1412, because Šibenik became in 1412 the seat of the main customs office and the seat of the salt consumers office with a monopoly on the salt trade in Chioggia and on the whole Adriatic Sea.