Battle of Araviana The Battle of Araviana was a cavalry action fought during the War of the Two Peters on 22 September 1359 . Eight hundred Aragonese horse , many of them Castilian exiles in service of the Crown of Aragon under Henry of Trastámara , had launched a " cavalgada " in Castilian territory when , near the Castilian town of Ágreda , confronted and routed a Castilian force under Juan Fernández de Henestrosa set to guard the frontier . Numerous Castilian noblemen and knights were killed , including Henestrosa , while many other were captured . Background . The War of the Two Peters broke in 1356 when a squadron of 9 Catalan galleys under Francesc de Perellós sent by the king Peter IV of Argon to assist the House of Valois in their succession conflict with the House of Plantagenet , captured near Sanlúcar de Barrameda two ships under the flag of the Republic of Genoa , at that time engaged in a war against the Republic of Venice and the Crown of Aragon . The king Peter I of Castile , who was present at Sanlúcar during the event , feel offended and demanded Perellós the free of the Genoese vessels . Perellós refused Peter ' s demands and was therefore chased by Castilian warships till the Portuguese coast . Peter of Castile complained afterwards to the king Peter IV Aragon , but as he did not obtained the desired results , he declared war on the Crown of Aragon . He promptly began the operations besieging by sea the Valencian town of Guardamar , unsuccessfully , and launching some " cavalgadas " through the frontier . In 1359 the Castilian fleet raided the Valencian and Catalan coasts , not obtaining satisfying results but menacing the town of Alicante . Peter IV , seeing that his southern frontier was in danger , dispatched several horse companies led by Pere de Xèrica to defend the area around Orihuela , Crevillente and Elche , and also ordered all the fortresses to be provisioned with enough ammunitions and supplies . Battle . Over the following months the action displaced to the Aragonese border with Castille . In September , Henry of Trastámara , pretender to the Castilian throne and half - broder and rival of Peter I , together with his younger brother Tello and several members of the Aragonese House of Luna , as Pedro , Juan Martínez and Fray Artal de Luna , launched a raid in Castilian territory invading the country near the town of Almazán . This force consisting of about 800 horse , encountered a considerable larger Castilian company of 1 , 500 horse led by the uncle of Peter I , Juan Fernández de Henestrosa . Refusing to run for cover , Henry offered battle near Ágreda . The fought which ensued was a brief affair and concluded with the routing of the Castilian force . Among those Castilians who were killed were found Juan Fernández de Henestrosa . Other signaled casualties were Gomez Suárez de Figueroa , Fernando García Duque , Pedro Bermúdez , Gonzalo Sánchez de Ulloa and Juan González de Bahabon . Many noblemen and knights as Iñigo López de Orozco , Fernando Rodríguez de Villalobos , Juan Gómez de Bahabon , Hurtado Díaz de Mendoza and Díaz Sánchez de Porra , all of them Knights of the Band , were captured . Also the Castilian banner was taken when his bearer , Gonzalo Sánchez de Ulloa , was killed . Aftermath . Peter I was informed of the defeat of his armies at his arrival on Seville from the Valencian coast . The Aragonese armies won another victory shortly after at Tarazon , but a few months later , in the spring of 1360 , Henry was defeated by Peter I himself at the so called First Battle of Nájera . On this occasion Henry was supported by 1 , 200 cavalry and 2 , 000 cavalry , while Peter had a much larger army of 5 , 000 cavalry and 10 , 000 infantry . Though Peter won the first day he decided to withdraw and Henry was able to continue offering battle . However , Castille took the initiative and focused the operations at the southern Valencian frontier . The town of Orihuela was subsequently raided by 800 Castilian and Moor cavalry , but a relief force of 250 horse led by Count Alfons of Ribagorza and Denia dispersed them and recovered the lost ground .