The shrine of Brotas is linked, according to legend, with a miracle about 1400: a cow grazing would have fallen to the bottom of the ravine on which the church stands today; a shepherd finding the dead animal proposed to skin it when the Virgin and Child appeared to him and told him to build a temple there in veneration of her image. Image that miraculously was carved of the bone of the leg of the cow, already amputated by the shepherd; after the apparition the shepherd noticed that the cow was alive and with the members intact.

The fame of the miracle took to the place numerous pilgrims in particular of the Alentejo and of the Peninsula of Setúbal. The number of pilgrims who came to the place was such a high number that the worship of the Virgin unfolded on the churchyard, on an exterior altar built for the purpose.

The cult of Our Lady of Brotas expanded rapidly outside Portugal, because the ships of the discoveries took its image.