Dating back from 3rd May 1282, it took place in several locations from the Fortress to the current area in the new town.

The weekly market, on Wednesdays, is one of the largest in Portugal, with over three hundred and fifty tents presenting clothing, home textiles, "rags", shoes, jewellery, local and regional handicrafts and seasonal fruits.

The fair, for its size and tradition, attracts a large number of national and Spanish visitors that contribute to the promotion of the fair and of local trade.