Battle of Barcelona ( 1359 ) The Battle of Barcelona ( June 9 – 11 , 1359 ) was a naval engagement fought in the coastal region of Barcelona , Spain , between the navies of the Crowns of Aragon and Castile , during the War of the Two Peters . A number of months beforehand , a large Castilian fleet had been assembled at Seville by order of the King of Castile , Peter I . Consisting of 128 warships including royal vessels , ships from the King of Castile ' s vassals , and several others that had been sent by the Castilian - allied monarchs of Portugal and Granada , this large fleet had been entrusted to the Genoese admiral , Egidio Boccanegra , who was seconded by two of his relatives , Ambrogio and Bartolome . With Peter I also on board , as well as many distinguished noblemen and knights , the Castilian fleet set sail from Seville in April . Traversing the coast of Valencia and forcing the surrender of the Castle of Guardamar , it appeared before Barcelona on June 9 . The king , Peter IV of Aragon and III of Barcelona , who was present at the city , organized the defense , together with the counts , Bernat III of Cabrera and Hug II of Cardona . The Catalans disposed of ten galleys , a nau , and several small craft garrisoned by companies of crossbowmen , besides a line of siege weapons . Despite its inferior size , the fleet managed to repulse the Castilian attacks in a two - day battle that saw the first use of naval artillery : a bombard was mounted aboard the Catalan nau and her shots heavily damaged one of the biggest naus of Peter I . Background . The " War of the Two Peters " broke out in 1356 , when a squadron of nine Catalan galleys under Francesc de Perellós ( sent by King Peter IV of Aragon to assist the House of Valois in their succession conflict with the House of Plantagenet ) captured two ships under the flag of the Republic of Genoa near Sanlúcar de Barrameda . At that time , the captured ships were engaged in a war against the Republic of Venice and the Crown of Aragon . King Peter I of Castile , who was present at Sanlúcar during the event , felt offended and demanded that the Genoese vessels be liberated from Perellós . Perellós refused Peter ' s demands and was chased by Castilian warships as far as the Portuguese coast . Peter of Castile complained afterwards to King Peter IV of Aragon , but as he did not obtain the desired results , he declared war on the Crown of Aragon . While both crowns promptly engaged in a bloody frontier war by land , in mid - 1358 the naval campaign began with the landing of a Castilian army at the Valencian town of Guardamar . Led by Peter I , they quickly occupied the town . Its castle , however , held out for longer , and when a storm drove most of the Castilian fleet ashore , including six hired Genoese galleys , Peter I had to set them on fire and return to Castile through Murcia , defeated . The following year Peter of Castile organized a larger expedition . Numerous ships were built at the shipyards of Seville , and many others were requested from Cantabria . The king , Peter I of Portugal , and Muhammed V , Sultan of Granada , also contributed ships to the increase in Peter ' s fleet . In all , the Castilian expedition numbered 128 vessels , of which twenty - eight galleys and two galiots were royal ships . Eighty others were Atlantic naus from the Cantabrian " Villas " , while the Portuguese and the Granadines sent ten and three galleys , respectively ; a Venetian nau was also hired . Peter hoisted his flag in a large nau captured from the Marinid s during the Siege of Algeciras by Alfonso X , which had been reinforced with three castles , one of them entrusted to the chronicler and naval captain , Pedro López de Ayala ; another was entrusted to Arias González de Valdés , while the third was overseen by García Álvarez de Toledo . The ship ' s crew consisted of 100 men - at - arms and 120 crossbowmen , along with its sailors and Peter ' s entourage . This fleet set sail on April and moved along the coast of Valencia , where the Castle of Guardamar was captured . On June 9 it was within sight of Barcelona . Battle . The naval forces gathered at the port of Barcelona consisted of ten well - armed galleys , several sailing ships and a very large vessel following the appearance of Peter I in the city . The forces were under the command of the generals , Bernat III of Cabrera and Hug II of Cardona , with Bernat and Gilabert de Cruilles , Bernat Margarit , and Pere Asbert as captains . The king , Peter of Aragon , took the command of the fleet and detached the galleys in a line along the beach , with the huge nau in middle of the line . All the vessels were covered by a shoal known as " " Las Tascas " " , which stretched from just before the Convent of Sant Nicolau de Bari to he road of Regomir . Four machines named " brigoles " were installed near the shores to give additional coverage to the ships , which were reinforced by many companies of crossbowmen who had come from the Vallès under the command of several knights including Ramón de Pujol , Ramón and Bernat Planella , Bernat de Perapetusa , Ramón Berenguer de Vilafranca and Humbert de Ballestar . Armed parties of Barcelona ' s civilians organized according to their office were also divided along the perimeter to support the fleet . According to the Castilian chronicler and captain López de Ayala , during the night the Catalans ran down numerous anchors before their line with the aim of keeping the Castilian ships as they approached the port to began the attack . Whether true or not , the Castilian fleet sailed through the shoals and a stubborn battle ensued . At nightfall , Peter I withdrew his vessels and the battle renewed at 10 AM , the following day . Then the Catalan crossbowmen inflicted heavy casualties upon the Castilian seamen and soldiers , and the Catalan artillery also caused serious damage to many ships . One of the biggest Castilian naus was hit twice by the fire of a bombard mounted aboard the largest Catalan nau , which demolished its castles and dismasted it . Aftermath . The Castilian fleet divided and part of the ships headed to the Llobregat river to get water . There they were confronted by many peasants of Barcelona and Sant Boi , and Peter I reorganized his forces and sailed to Ibiza , where he placed its castle under siege . Peter IV gathered a force of 50 galleys collected from Collioure , which he entrusted to Admiral Count of Osona with Cardona as vice - admiral . Relieving the island , the Castilian army left the siege and reembarked . Though he had numerical advantage , Peter I chose not to join the battle and withdrew . He was pursued by 15 or 20 galleys under Bernat de Cabrera . This force then anchored at the Denia estuary . The Castilians were then willing of fight , but as the Aragonese position was strong and supported by land forces , Peter I decided to sail back to Seville . Upon his arrival , Peter found that his armies had been defeated on 22 September in the largest land battle of the war at Araviana .