The history of Póvoa de Varzim, Portugal, and its development as a maritime trade and fishing hub, have been greatly influenced by its location at the entrance to one of Portugal's best natural ports. Permanent settlement in the coastal plain of Póvoa de Varzim dates back to around four to six thousand years ago; around 900 BC, unrest in the region led to the establishment of a fortified city. The ocean has played an important part in its popular culture and economy, through maritime trade and fishing, leading it to establish a fiefdom in the 10th or 11th century, a municipality in 1308 and to become, in the 18th century, the main fishing port in northern Portugal.