Treviso (Latin: Tarvisium) was founded in Roman times, and it was an important city of Byzantine Venetia, then a Lombard duchy, and a Venetian regimento.
Following the Lombard invasion and conquest of Venetia, a part of the Venetian population of the mainland cities fled or left for the settlements in the nearby lagoons.
The Lombard invasion of Byzantine Italy in 568 was a pivotal event in Venetian history, as it kicked off the movement towards a distinct Venetian society, culture and, ultimately, state.