Spánverjavígin also known as the "Spanish Killings" or "Slaying of the Spaniards" was the last documented massacre in Icelandic history. Some Basque whalers went on a whaling expedition to Iceland and were killed after conflict in 1615 with local people in the region of the Westfjords.
In the first half of the sixteenth century Basque whalers set up the world's first large-scale whaling industry in Terra Nova. The center of this industry was some ten ports on the southern coast of Labrador. During the peak years of the 1560s and 1570s the fleet comprised around 30 ships manned by up to 2,000 men, who killed in the region 400 whales each year. By the beginning of the seventeenth century Basque whaling had reached Iceland.
The year 1615 was a difficult year in Iceland with ice up to shores until late summer and considerable loss of livestock. In mid-summer three Basque whaling vessels put into Reykjarfjörður in Westfjords. Icelanders and the Basques had a mutual agreement at the beginning as they both had benefited from the enterprise. When the ships were ready for departure in late September a terrible gale arose and the ships were driven on the rocks and crushed. Most of the crew members survived (approx. 80). The captains Pedro de Aguirre and Esteban de Telleria wintered at Vatneyri (Patreksfjörður) and left for home the following year. The crew of Martin de Villafranca's ship split into two groups; one entered Ísafjarðardjúp, the other went to Bolungarvík and later to Þingeyri.
The first conflict arose when one group entered the empty house of a merchant of Þingeyri and took some dried fish. As retaliation, on 5 October, at night, a group of Icelanders entered the hut where the Basques were sleeping and killed 14 of them, only one young man called García, escaped. Captain Martín de Villafranca of San Sebastián, whose father and grandfather had both been involved in Terra Nova whaling was among those who were killed. The bodies were mutilated and sunken into water. Jón Guðmundsson the Learned wrote about the injust and cruel deaths " dishonored and sunken into sea, as if they were the worst pagans and not innocent christians". Three days after the first slaying, Ari Magnússon summoned a council at Súðavík and twelve judges agreed to declare as outlaws all the Basques.
On 13 October Martin and the other 17 of his group were killed at Æðey and Sandeyri in Ísafjarðardjúp, while they were fishing by the troops commanded by Ari Magnússon. According to Jón Guðmundsson, the victims were stabbed in the eyes, their ears, noses and had their genitals mutilated. The captain, Martín de Villafranca, was injured in the shoulder and chest with an axe, but he managed to escape into the sea however he was stoned in the water and dragged to the shore where he was tortured to death.
Two verdicts were instigated by sheriff Ari Magnússon of Ögur, Ísafjarðardjúp in October 1615 and January 1616. The Basques were considered criminals after their ships were wrecked and in accordance with the Icelandic law book of 1281 it was decided that the only right thing to do was to kill as many of them as possible.
Jón Guðmundsson the Learned (1574–1658) wrote a critical account condemning the decision of the local sheriff to order the killings: Sönn frásaga af spanskra manna skipbrotum og slagi (A True Account of Spanish Men's Shipwrecks and Slayings). Jón says that they were unjustly killed; not wishing to take part in an attack on them, he fled south to Snæfellsnes.