Muslim strongholds in the Guadalquivir Valley such as Córdoba (1236) and Seville (1248) fell to Castile in the 13th century. The County of Barcelona and the Kingdom of Aragon entered in a dynastic union and gained territory and power in the Mediterranean. In 1229 Majorca was conquered, so was Valencia in 1238. In the 13th and 14th centuries, the North-African Marinids established some enclaves around the Strait of Gibraltar. From the mid 13th century, literature and philosophy started to flourish again in the Christian peninsular kingdoms, based on Roman and Gothic traditions. An important philosopher from this time is Ramon Llull. Abraham Cresques was a prominent Jewish cartographer. Roman law and its institutions were the model for the legislators. The king Alfonso X of Castile focused on strengthening this Roman and Gothic past, and also on linking the Iberian Christian kingdoms with the rest of medieval European Christendom. Alfonso worked for being elected emperor of the Holy Roman Empire and published the Siete Partidas code. The Toledo School of Translators is the name that commonly describes the group of scholars who worked together in the city of Toledo during the 12th and 13th centuries, to translate many of the philosophical and scientific works from Classical Arabic, Ancient Greek, and Ancient Hebrew. The 13th century also witnessed the Crown of Aragon, centred in Spain's north east, expand its reach across islands in the Mediterranean, to Sicily and Naples. Around this time the universities of Palencia (1212/1263) and Salamanca (1218/1254) were established. The Black Death of 1348 and 1349 devastated Spain. In 1311, Catalan mercenaries won a victory at the Battle of Halmyros, seizing the Frankish Duchy of Athens. The royal line of Aragon became extinct with Martin the Humane, and the Compromise of Caspe gave the Crown to the House of Trastámara, already reigning in Castile. As in the rest of Europe during the Late Middle Ages, antisemitism greatly increased during the 14th century in the Christian kingdoms. (A key event in that regard was the Black Death, as Jews were accused of poisoning the waters.) There were mass killings in Aragon in the mid-14th century, and 12,000 Jews were killed in Toledo. In 1391, Christian mobs went from town to town throughout Castile and Aragon, killing an estimated 50,000 Jews. Women and children were sold as slaves to Muslims, and many synagogues were converted into churches. According to Hasdai Crescas,