according to an old legend, it was near the bank of the trancão that the mythical battle of sacavém river took place, between king afonso i of portugal and the moors, in october 1147. the tradition (fixed probably in the 16th century) says that the moorish people had gathered around 5,000 men from all estremadura (alenquer, óbidos, tomar, torres novas and torres vedras) to fight against only 1500 christians, but the latter defeated the muslims in a large blood bath, with this wondrous victory personally attributed to the intervention of the holy virgin, which brought many christians speaking strange languages (this is, the crusades that took lisbon that same year).