Fão was the city of the mouth of the Cávado, because the Cávado flowed further south, before being silted up, and its bar moved north in front of Esposende.

When this happens, from the 10th - 11th centuries onwards, its fort became the salt flats.

Then came the activity of building boats, with its shipyard next to the current metal bridge. Fão boasted of the speed of his boats, which no pirate or privateer would ever have managed to reach or capture.