Source en.wikipedia.org
Umag was mentioned for the first time in the 7th century by an anonymous citizen from Ravenna, but it already existed in Roman times. Proof of this is found in the numerous remains of Roman villas, the so-called villa rustica uncovered all along the coast. The town's history is closely linked to the settlement of Sipar, whose ruins can be found on a narrow cape four kilometres north of Umag. In the 9th century, the fortified settlement of Sipar was devastated by invaders, the Neretva pirates. However, after this unfortunate incident Umag grew in significance thanks also to its location, a small islet separated from the mainland by a narrow channel. It was actually this location that safeguarded the settlement from the continuous invasions down through the centuries. The Roman period of relative prosperity was interspersed with one of insecurity caused 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 ranging from the Patriarchs of Grado and Aquileia to the Bishops of Trieste. However, the increasingly powerful Venetian Republic imposed its rule over Istria, forcing Umag and other western Istrian towns to swear loyalty to Venice. In fact, in 1269, the Commune of Umag swore loyalty to Venice which from that time on 1797 was to appoint governors of Umag from among its nobility. This period was by no means a peaceful one.
Century-old clashes with Genoa brought about more destruction and looting. In 1370 the Genoese navy attacked Umag, destroying the town's archive. The outbreaks of plague that decimated the inhabitants forced the Venetian authorities to consider colonising the area with new settlers, mainly from the territories threatened by Turkish invasions. The harbour of Umag was utilised for loading agricultural surplus from the hinterland. Up to the collapse of Venice Umag had lived like other Istrian towns. Its communal arrangement was guaranteed by Statute from 1541.
With the fall of the Venetian Republic, Umag, like the entire eastern Adriatic coast, came under the rule of France until 1815 when it passed over to Austria until 1918. With the end of World War I Istria became part of Italy. After World War II, the flaring up of the Trieste crises resulted in the establishment of the Free Territory of Trieste, while Umag became part of Zone B governed by the Yugoslav Army, and eventually became part of SR Croatia within SFR Yugoslavia in 1954. After Umag became part of Yugoslavia, there was an exodus of many Italians from the town, who, until then, had constituted the majority of its population.
In 1993, with the establishment of the new local rule, Umag became an independent municipality, and, in 1997, was awarded the status of town (grad).