Oiasso

Oiasso was a Vascon town of the Roman Empire on the left bank of the Bidasoa estuary on the Bay of Biscay, its remains found beneath the old quarter of modern Irún in Gipuzkoa, Spain, near the French border. It served as a customs crossing between Aquitaine and Hispania Citerior, with duties charged on goods moving in each direction, and supported Roman silver and copper mining in the surrounding area. Roman road construction at the end of the 1st century BCE increased the town's importance as an Atlantic trade port.