Located along the Douro river estuary in northern Portugal, Porto is one of the oldest European centres, and registered as a World Heritage Site by UNESCO in 1996. Its settlement dates back many centuries, when it was an outpost of the Roman Empire. Its Latin name, Portus Cale, has been referred to as the origin for the name “Portugal”, based on transliteration and oral evolution from Latin.
In Portuguese the name of the city is spelled with a definite article as “o Porto”(ENGLISH: the port). Consequently, its English name evolved from a misinterpretation of the oral pronunciation and referred to as “Oporto” in modern literature and by many speakers.