History of Poreč begins before more than 2000 years when old Romans conquered Histrian aborigines and founded the castrum (military facility) on the 400 m long and 200 m wide peninsula. During the reign of Emperor Augustus in the 1st century the castrum was officially promoted to a city and it became administrative and economic center of Roman colony Colonia Iulia Parentium. The first bishop of Poreč, Mavar, was prosecuted by Roman authorities and after his death he became a patron saint (Saint Maurus), protector of the city. On the site of bishop's sacrifice a Christian cathedral was founded in the 4th century. In the 6th century the bishop Eufrasius built a basilica this same place.
After the fall of the Roman Empire, Ostrogoths rule the city, than after the year 539 the Byzantine Empire. At the end of the 6th century Croats settle around Poreč, and after the year 788 the city falls under the rule of Franks. A short period of independence followed in the 12th century. In 1267 Poreč fell under the rule of Venice. In this period beautiful gothic palaces and towers are built. In 1363 the Statute of Poreč was proclaimed. In 1797 Poreč falls under the rule of Napoleon Bonaparte, than in 1814 it becomes part of Austro-Hungarian Empire.
Austrian vapor-ship company Lloyd from Trieste started in 1844 a tourist line including the city of Poreč. In 1845 the first tourist guide with pictures and description of Poreč was printed. In 1861 Poreč became the capital of Istria, the seat of regional (Istrian) parliament, with schools, administrative and judiciary offices.
Austro-Hungarian aristocracy discovered Poreč in 1866, when Austrian archduchess Stephanie presented the city to the public by sailing into the city harbour on her yacht Phantasy. In 1902 a narrow-gauge railroad between Poreč and Trieste was built, named Parenzana. In 1910 the first hotel in Poreč, Riviera, was built. From 1920-1943 Poreč was ruled by the Kingdom of Italy and in 1943, with the rest of Istria, Poreč became a part of Croatia.