The word Portugal derives from the Roman-Celtic place name Portus Cale; a city where present-day Vila Nova de Gaia now stands, at the mouth of the River Douro in the north of what is now Portugal. The name of the city is from the Latin word for port or harbour, portus, but the second element of Portus Cale is the subject of numerous theories. The mainstream explanation for the name is that it is an ethnonym derived from the Castro people, also known as the Callaeci, Gallaeci or Gallaecia, a people who occupied the north-west of the Iberian Peninsula. The names Callaici and Cale are the origin of today's Gaia and Galicia.
Another, romantic theory has it that Cala was the name of a Celtic goddess (drawing a comparison with the GaelicCailleach a supernatural hag). A further theory is that Cale or Calle is a derivation of the Celtic word for port, like the Irish caladh or Scottish Gaelic cala. These explanations however would require the pre-Roman language of the area to have been a branch of Q-Celtic, which is not generally accepted. The region's pre-Roman language was Gallaecian Celtic.
Some French scholars believe the name may have come from 'Portus Gallus', the port of the Gauls or Celts.
Around 200 BC, the Romans took the Iberian Peninsula from the Carthaginians during the Second Punic War, and in the process conquered Cale renaming it Portus Cale (Port of Cale) incorporating it to the province of Gaellicia with capital in Bracara Augusta (modern day Braga, Portugal). During the Middle Ages, the region around Portus Cale became known by the Suebi and Visigoths as Portucale. The name Portucale evolved into Portugale during the 7th and 8th centuries, and by the 9th century, that term was used extensively to refer to the region between the rivers Douro and Minho. By the 11th and 12th centuries, Portugale, Portugallia, Portvgallo or Portvgalliae was already referred to as Portugal.