From the second half of the 1st century the town acquired the rank of a colony named Colonia Julia Parentium. It is important that with this Porec had the status, in particular rights and liberties, of the other most important towns of the Roman Empire. Like the other Roman towns Porec has the characteristic regular screen of streets which criss cross at right angles forming themselves rectangular house blocs named “insulas”.

The main longitudinal street Decumano runs in the east west direction with the main transversal Cardo street that vertically intersect it. The basic distribution of Roman streets remained intact in the Middle Ages.

Porec was considered town since long time ago, because it was a Bishopric seat and it has very old Roman Municipality tradition.

After the fall of the Roman Empire Porec was part of Odoacre kingdom from 476 until 493 and later on of the King Teodorico. In that period Porec had relations with Ravenna that was the capital of Ostrogoths kingdom.

From 539 Porec was part of the Byzantine Empire and few years later Bishop Euphrasian started to built his Basilica using the best artists from Ravenna. At the beginning of the 7th century Porec and most of the Istrian territories were attacked for several times by barbarians during the first decade of the century. This attacks lasted until 611.

In 728 due to a new rule approved by Byzantine Emperor the iconoclasm phenomenon happened. The Pope and Byzantine Emperor were in disagreement and Longobard King took advantage of this situation and defeated Byzantines and conquered Istria and Porec in 751.

In 774 Porec returned to Byzantine Empire but few years later, in 788, was conquered by Carolingian. In that period Porec lost the Municipality order, while the Bishops increased significantly their power and decline of Porec’s cultural life started.

Most of the feudal Lords and Bishops that came into the town were foreigners but after years they integrated with the local population. In 964 Porec suffered Croatian pirates attacks. This happened to many other Istrian towns on the coast in that period. Bishops of Porec were rich and strong in that period.

It is interesting that in 983 they nominated themselves Counts of Vrsar. A part from Vrsar, they owned several other Istrian territories. Most of the properties that Bishops of Porec received were the donations from the other Kings like: Ugo of Provence in 929, Ottone II in 983 and other donations from the Aquileia Patriarchs.

Porec’s Bishops were also in disputes with the Aquileia Patriarchs regarding some territories occupied by the Aquileia Patriarchs for almost two centuries. In particular the dispute were related with Bale, Rovinj and Dvigrad. It is interesting that already in year 1000 there was a first agreement between Porec and Venice in order to destroy Croatian pirate attacks in the area.

In 1081 the Aquileia Patriarchs obtained Porec from Enrico IV. In 1150 Porec signed another fidelity agreement with Venice and already in 1207 tried to exist from it, but it was not successful.

The problem was that Venetian ships were using Porec harbour without paying anything for that. The whole 12th century passed in litigations between Porec Bishops and the Municipality that represented the population of the town.

In 1194 the old Municipality laws were restored and few years later, in 1199, Porec signed a friendship and commercial agreement with Dubrovnik.

In 1209 the Aquileia Patriarchs returned to rule over Porec and in 1249 they decided to restore the town walls and the defence towers. In 1230 few towns on the coast have tried to organize an alliance in order to resist against the Aquileia Patriarchs rule and to protect the Municipality rights but one by one were returned under the Aquileia Patriarchs control.

In that years there was another Istrian town that gained importance thanks to the salt trading and that was Kopar. Kopar was allied with Counts of Gorizia.

In 1267 they attacked Porec and Porec in that year formally became part of the Venetian Republic. Porec was the first Istrian town to join Venice Republic. In the decades before the passage to Venice, Porec’s Bishops have sold to the Count of Gorizia most of the territories that in the past were belonging to Porec.

In 14th century Venice was in war with Genova and, in 1354, their Admiral Paganino Doria occupied Porec and took to Genova the bones of the martyr Saints. As wrote above they were returned to Porec only in 1934.

In 1361 Porec suffered plague that was the most terrible illness of the last centuries in Istria. Few decades later, in 1411, Porec suffered and resisted against the attacks of the Hungarian King Sigismondo.