primarily by frequent invasions, outbreaks of plague, cholera, and malaria. The number of its inhabitants declined rapidly. Umag became part of the reigns of Odoacer, Theodoric, and was also ruled by the Langobards.

From the 6th to the 8th centuries it fell under Byzantine dominion, followed by the rule of the Lombards in 751 and Francs in 774. The subsequent period was marked by insecurity and frequent changes of government