Tragedy and opportunity arose from plague, anti-Jewish fight intensity and political calamity caused by the sudden and unexpected death of Castilian King Alfonso XI, who in 1350 succumb to the black plague. From 1347 to 1350, approximately 25 million died of the plague in Europe, or 25 percent of the population. In fact, the pandemic returned multiple times in Castile, were surging in 1374 and 1384. Over the course of the 14th century, Liberian population withered from an estimated population of 4.5 million persons. one million died from the disease. Across Europe, Jewish communities were implicated as the cause of the illness. Complicating this natural phenomena was a persistent division separating Christians and Jews. Samuel M. Cohn Jr. reminds the reader that, "Jews were accused of poisoning food, wells and streams, tortured into confessions, and rounded-up in cities squares or their synagogues and exterminated en masse." In particular, in Germany, Southern France and Spain, the burning the Jews was far reaching. Crisis, the death of the King. The Cronica de los Reyes de Castilla did not implicate the Jewish community in the death of King Alfonso XI, but instead relays the monarch died as another helpless victim at the plague. Quote, "By laying siege to Gibraltar and after the battles and conquests by the noble prince Lord King Alfonso of Castile and Leon, it was at the village and the noble, notable, very strong castle of Gibraltar. The plague entered among Muslims and Christians. By the will of God, this pestilence of the greatest mortality returned and fell upon our most noble King Alfonso." Civil war in Castile, Pedro the Cruel and Enrique II de Trastamara. Hostilities between the half brothers commenced as early as 1353 when Enrique fielded 600 knights and 1500 Asturian men at arms in the village of Sagittarius to meet Pedro I military companies coming from the nearby city of Valladolid. Joining Enrique's endeavour to uncrown Pedro I were many noble families such as Count I Afonso de Albuquerque. The Count's allegiance to Enrique was reflective of the challenges and the choices the old nobility often described as such due to their longstanding pedigree and presence in Castilian affairs who faced during the civil war. Who should they support? The legitimate heir to the throne Pedro I, or the illegitimate Enrique II? Also complicating the political environment and battlefield was Pedro I war with Peter III, the King of Aragon, who had his own design for control over the Iberian Peninsula. By its nature, the civil war that Pedro I waged was according to LJ Andrew Villalon a quote, "bloody Iberian episode. And the monarch employed terror as a major military strategy and external terror directed against the enemy, and an internal one aimed at inspiring his own followers to greater efforts." Royal directives ordered Castilians loyal to Pedro I to wage the cruelest war you can. Supporting this efforts were old noble families, like the Fernandes, the Hanun Krasa, Suarez the Figaroa, Fernandes the Toledo, and the Benevides. By 1360, Pedro I seemed to be in a stronger position to garner the upper hand in the kingdom, after he had three of his half brothers executed and signed a peace accord with the kingdom of Aragon. The remaining impediment to his consolidation of control of Castile with his brother Enrique II. Among the many complaints raised by Enrique II, was that his half brother was far too sympathetic to religious minorities, and was overly dependent on Jewish advisers and Muslim men at arms. On several occasions during the civil war, Enrique II besieged Jewish communities and Toledo embargos. It would prove an odd outcome that Enrique II and his eventual victory over Pedro I, were turned to Jewish converts to Christianity, as he built his devastated price, the Kingdom of Castile Leon. The contest was also an internationalized conflict, as several Spanish Christian kingdoms, England and France, politically and militarily wrestled with each other on the continent during the opening of the 100 Years War. England and France both courted Castile as a strategic ally in their continental war, which in 1362 pulled for Pedro I into an alliance with King Edward III England, and in 1363 prompted France to recognize Enrique as the legitimate heir to the crown of Castile. None until 1369 was the conflict for the Crown resolved, when Enrique II and Pedro I fought the fateful battle of Montiel. At Montiel, Pedro was defeated and took refuge in his castle. When Enrique II sent his emissary Mosen Beltran to his half brother to negotiate. Pedro sought Beltran's assistance to betray Enrique II, making him a generous offer, as a chronicle of Pedro Lopez d'Ajala detailed. Pedro said if he, Mosen, will liberate him from here safely and securely, he would give to him and those who succeeded him the villages of Soria, Almazan, Atienza, Monteagudo, Deza and Seron, as well as 200,000 Castilian gold pieces, doblas. Although Beltran agreed to the treachery, he informed Enrique II of the plan, and led him to where Pedro was holed up there where the two met face to face. According to Pedro Lopez, the bitter war had inflicted damage to both men's memory as well, so much so that Enrique II did not recognize his half brother. In the presence of Pedro I, one of Beltran's knights said to Enrique II, "This man is your enemy". And to this statement Pedro the first replied, "I am. I am." With a dagger, Enrique II struck his half sibling in the face, and the two fell to the ground and there died King Pedro on the twenty third day of March of the said year. With Pedro's death in 1369, Enrique became the founding head of the Trastamaran Dynasty, which would culminate in the unification of Spain under Isabella Castile and Ferdinand of Aragon in 1469. The twin stresses of political disintegration and disease, facilitated a unique political and cultural change in Castilian cultural history. The consequences of Pedro's death and Enriques victory were socially and politically enormous, as the Castilian nobility was exhausted from almost two decades of civil war.