| Partof: | the Reconquista |
| Date: | July 1147 |
| Place: | Sacavém, near Trancão River |
| Result: | Christian victory |
| Combatant1: | Kingdom of Portugal Crusaders |
| Combatant2: | Taifa of Badajoz |
| Commander1: | Unknown |
| Commander2: | Bezai Zaide, wali of Sacavém |
| Strength1: | + 1,500 |
| Strength2: | 5,000 |
| Casualties1: | N/A (very high) |
| Casualties2: | c. 3,000 killed in action (most of whom drowned on the river) c. 2.000 captured |
The mythical battle of Sacavém was a military clash between the first Portuguese king, Afonso Henriques, and the Moors from the taifa of Badajoz, at the beginning of the siege of Lisbon, that took place in early July 1147, on the shores of the Trancão River, near the old Roman bridge that, according to several ancient sources, crossed the river in the town of Sacavém, at the time know as Šaqabān (Arabic: شقبان).
After conquering Santarém, in March 1147, Afonso Henriques prepared to take Lisbon and thus consolidate definitively the line of control around the Tagus valley.
Following the occupation of Santarém, news spread throughout the region that Christians were already besieging Lisbon, thus it was making it essential to help defend the last Muslim strongholds to the north of the Tagus at all costs.
Therefore, around five thousand Muslims from Alenquer would have gathered in the vicinity of Sacavém, as well as from Óbidos, Torres Vedras) and Tomar, under the command of the Muslim qaid of Sacavém, Bezai Zaide.
According to the legend, the Portuguese only had a force of 1500 Christians against 5000 Moors, who already had begun the crossing of the old Roman bridge, ready to destroy the Portuguese. Despite the significant difference between the two opponents, the Christian side eventually won; most of the Muslims were either killed with the swords or drowned in the river.
This miraculous victory was attributed to the intervention of the Holy Virgin Mary which, according to the tradition, made many strange men who were fighting with the Christians appear during the battle. As Afonso Henriques had the support of the Crusaders to take Lisbon, it is very likely that these strange men were foreigners, that is, the Crusaders from Northern Europe.
It is said that Bezai Zaíde converted to the Christian faith after the battle, and became the first eremite of hermitage that was established near the place of the battle, dedicated to Our Lady of Victory.
The first to refer to this legend was the cistercian friar from Alcobaça, António Brandão,[1] claiming that it was based on an old tradition gathered among the people of Sacavém; Miguel de Moura, in his unpublished Memories of the Establishment of Monastery of Sacavém, also refers to this legend among the people of Sacavém, which he had investigated when he wanted to build a Monastery in the town, on the site of the old hermitage of Our Lady of Martyrs, in 1577.
However, there is no historical evidence that confirms the actual existence of this skirmish; the sources regarding the conquest of Lisbon, such as the well-known De expugnatione Lyxbonensi, which provides a detailed account of the siege, make no reference to this clash on the banks of the Trancão River.
In the 19th century, the Portuguese historian and politician Alexandre Herculano was the first to question this fact in his well-known History of Portugal. Nowadays, it is commonly considered to be a legend, at least in the form in which it was described.