Poreč (ˈpɔrɛtʃ; Parenzo; Parenso; Parens or Parentium; Párenthos) is a town and municipality on the western coast of the Istrian peninsula, in Istria County, west Croatia. Its major landmark is the 6th-century Euphrasian Basilica, which was designated a UNESCO World Heritage Site in 1997.
The town is almost 2,000 years old, and is set around a harbour protected from the sea by the small island of Sveti Nikola/San Nicola (Saint Nicholas). Its population of approximately 12,000 resides mostly on the outskirts, while the wider Poreč area has a population of approximately 16,600 inhabitants. The municipal area covers , with the long shoreline stretching from the Mirna River near Novigrad (Cittanova) to Funtana (Fontane) and Vrsar (Orsera) in the south. Ever since the 1970s, the coast of Poreč and neighboring Rovinj (Rovigno) has been the most visited tourist destination in Croatia.
This area has been inhabited since prehistoric times.
During the 2nd century BC, a Roman castrum was built on a tiny peninsula with approximate dimensions of where the town centre is now. During the reign of Emperor Augustus in the 1st century BC, it officially became a city and was part of the Roman colony of Colonia Iulia Parentium.
In the 3rd century the settlement had an organised Christian community with an early-Christian complex of sacral buildings. The earliest basilica contained the remains of and was dedicated to Saint Maurus of Parentium and dates back to the second half of the 4th century. The floor mosaic from its oratory, originally part of a large Roman house, is still preserved in the garden of the Euphrasian Basilica.
With the fall of the Western Roman Empire in 476, different rulers and powers governed. First, it was held by the Ostrogoths and after 539 was part of the Byzantine Empire. From 788 it was ruled by the Franks. A short independence period followed in the 12th century and later it was ruled by the Patriarchate of Aquileia. In 1267 Parenzo became the first Istrian city that chose to become part of the Republic of Venice, whose rule lasted for more than five centuries.