According the legend, in 1362 the statue of Our Lady of Grace appeared in the network of a fishermen who had come to deliver to the Convent of Grace the next day. Portugal was in war with Castilla (kingdom of Spain) and the statue of Our Lady of Grace announced the victory of the armies of the portuguese King John.
Initially the convent was founded at Mount St. Gens - where the first King of Portugal camped with his troops during the siege of Lisbon in 1147. Founded by the Hermits of St. Augustine in 1271, this convent underwent numerous changes since then.