The Alvor massacre took place in June 1189 during the Third Crusade, when a fleet of crusaders from the Holy Roman Empire, Denmark and the County of Flanders stormed the castle of Alvor in the Algarve, then part of the Almohad Caliphate, and massacred 5,600 people. The place of the conquest and massacre of Alvor in the Portuguese Reconquista is unclear, but there are grounds for thinking that it was part of the strategy of King Sancho I, who launched a siege of Silves a month later.
Expedition
In February 1189, fifty or more ships carrying perhaps 12,000 men sailed from Frisia. At the mouth of the Rhine, they joined with another fleet consisting of crusaders from the Rhineland, Holland and Flanders. From there, they sailed to Dartmouth, joining further squadrons of English and Flemish ships. According to Lambertus, the fleet had 55 ships and contained Danes, Flemings, Frisians and men from Cologne and Liège.
The Royal Chronicle records that the fleet set sail during Lent. Ten days after setting out, it stopped in Galicia. At that time it contained 60 ships of various origins with "10,000 fighting men and more." The crusaders attempted to visit the shrine of Saint James at Compostela. A rumour spread that they intended to steal James's relics and there was fighting between the pilgrims and the townspeople resulting in fatalities on both sides before, "through wise men intervening," the crusaders agreed to return to their ships. The fleet then stopped in Lisbon before attacking Alvor, as recorded in the Seaborne Journey:
The ships from our empire and from Flanders had arrived some four or five weeks before us [around 29 May – 6 June], and on their voyage beyond Lisbon they had stormed a fortified town named Alvor, subject to the lordship of Silves, and we were reliably informed that, sparing neither age nor sex, they slew some 5,600 people. Galleys from Lisbon accompanied them until they reached the Straits [of Gibraltar] and then they returned. They informed us that they were making a good voyage, and they brought back some captive Saracens… On the afternoon of the third day [July 17] we saw the town of Alvor, which our men had captured and destroyed, overlooking the sea, as well as other abandoned places whose inhabitants had been killed at Alvor.
To this account of the massacre, the Royal Chronicle adds the detail that they "captured endless amounts of silver and gold." After the sack, the men of Cologne chose to remain in Portugal while the rest of the expedition continued eastward. Lambertus confirms that the fleet eventually joined the siege of Acre. It is the fleet that arrives on 1 September in the account of Arnold of Lübeck and is also mentioned by Ralph of Coggeshall. The Itinerary of the Pilgrims records its arrival, but conflates it with the fleet that captured Silves and mistakenly transplants the massacre to that city.
The leaders of the fleet that sacked Alvor are unnamed in any source. The crusaders seem mainly to have been commoners. The event cannot be dated more precisely than to the month of June. Neither is it clear how long it took to reduce Alvor. It was probably stormed, since the chronology leaves no room for a lengthy siege. Following the capture of Silves, Sancho I granted Alvor to the monastery of Santa Cruz.
Place in the Reconquista
No source states explicitly that the crusaders who attacked Alvor were acting in agreement with Portugal, but it is likely that they were. The fleet was in Lisbon prior to the sack and was accompanied as far as the Straits of Gibraltar by some Portuguese galleys. Moreover, the sack of Alvor was of strategic value for King Sancho I's impending attack on Silves.
The massacre at Alvor was exceptional in the Portuguese Reconquista. The normal policy was to encourage Muslim populations to remain to keep the land under cultivation and to pay taxes to the king. The indiscriminate massacre shocked contemporaries. The sack of Alvor is unrecorded in medieval Portuguese historiography, possibly it was even suppressed. In the account of Sancho I's reign in the Chronicle of 1419, the capture of Silves is recounted in detail, but Alvor is not mentioned.
Alvor was retaken by the Almohads during their campaign of 1191.