Alfonso I (c. 1073/1074 – 7 September 1134), called the Battler or the Warrior (Spanish: el Batallador), was King of Aragon and Navarre from 1104 until his death in 1134. He was the second son of King Sancho Ramírez and successor of his brother Peter I. With his marriage to Urraca, queen regnant of Castile, León and Galicia, in 1109, he began to use, with some justification, the grandiose title Emperor of Spain, formerly employed by his father-in-law, Alfonso VI. Alfonso the Battler earned his sobriquet in the Reconquista. He won his greatest military successes in the middle Ebro, where he conquered Zaragoza in 1118 and later took Ejea, Tudela, Calatayud, Borja, Tarazona, Daroca, and Monreal del Campo. He died in September 1134 after an unsuccessful battle with the Muslims at the Battle of Fraga.
Alfonso's nickname comes from the Aragonese version of the Chronicle of San Juan de la Peña (c. 1370), which says that "they called him lord Alfonso the battler because in Spain there wasn't as good a knight who won twenty-nine battles" (clamabanlo don Alfonso batallador porque en Espayna no ovo tan buen cavallero que veynte nueve batallas vençió).
His earliest years were passed in the monastery of Siresa, learning to read and write and to practice the military arts under the tutelage of Lope Garcés the Pilgrim, who was repaid for his services by his former charge with the county of Pedrola when Alfonso came to the throne.
During his brother's reign, he participated in the taking of Huesca (the Battle of Alcoraz, 1096), which became the largest city in the kingdom and the new capital. He also joined El Cid's expeditions in Valencia. His father gave him the lordships of Biel, Luna, Ardenes, and Bailo.
A series of deaths put Alfonso directly in line for the throne. His brother's children, Isabella and Peter (who married María Rodríguez, daughter of El Cid), died in 1103 and 1104 respectively.
A passionate fighting-man (he fought twenty-nine battles against Christian or Moor), he was married (when well over 30 years and a habitual bachelor) in 1109 to the ambitious Queen Urraca of León and Castile, a passionate woman unsuited for a subordinate role. The marriage had been arranged by her father Alfonso VI of León in 1106 to unite the two chief Christian states against the Almoravids, and to supply them with a capable military leader. But Urraca was tenacious of her right as queen regnant and had not learnt chastity in the polygamous household of her father. Husband and wife quarrelled with the brutality of the age and came to open war, even placing Urraca under siege at Astorga in 1112. Alfonso had the support of one section of the nobles who found their account in the confusion. Being a much better soldier than any of his opponents he won the Battle of Candespina and the Battle of Viadangos, but his only trustworthy supporters were his Aragonese, who were not numerous enough to keep Castile and León subjugated. The marriage of Alfonso and Urraca was declared null by the pope, as they were second cousins, in 1110, but he ignored the papal nuncio and clung to his liaison with Urraca until 1114. During his marriage, he had called himself "King and Emperor of Castile, Toledo, Aragón, Pamplona, Sobrarbe, and Ribagorza" in recognition of his rights as Urraca's husband; of his inheritance of the lands of his father, including the kingdom of his great-uncle Gonzalo; and his prerogative to conquer Andalusia from the Muslims. He inserted the title of imperator on the basis that he had three kingdoms under his rule.
The king quarrelled with the church, and particularly the Cistercians, almost as violently as with his wife. As he defeated her, so he drove Archbishop Bernard into exile and replaced the abbot of Sahagún with his brother. He was finally compelled to give way in Castile and León to his stepson, Alfonso VII of Castile, son of Urraca and her first husband. The intervention of Pope Calixtus II brought about an arrangement between the old man and his young namesake.
In 1122 in Belchite, he founded a confraternity of knights to fight against the Almoravids. It was the start of the military orders in Aragon. Years later, he organised a branch of the Militia Christi of the Holy Land at Monreal del Campo.
Alfonso spent his first four years as king in near-constant war with the Muslims. In 1105, he conquered Ejea and Tauste and refortified Castellar and Juslibol. In 1106, he defeated Ahmad II al-Musta'in of Zaragoza at Valtierra. In 1107, he took Tamarite de Litera and San Esteban de Litera.
Then followed a period dominated by his relations with Castile and León through his wife, Urraca. He resumed his conquests in 1117 with Fitero, Corella, Cintruénigo, Murchante, Monteagudo, and Cascante.
In 1118, the Council of Toulouse declared a crusade to assist in the conquest of Zaragoza. Many Frenchmen consequently joined Alfonso at Ayerbe. They took Almudévar, Gurrea de Gállego, and Zuera, besieging Zaragoza itself by the end of May. The city fell on 18 December, and the forces of Alfonso occupied the Azuda, the government tower. The great palace of the city was given to the monks of Bernard. Promptly, the city was made Alfonso's capital. Two years later, in 1120, he defeated a Muslim army intent on reconquering his new capital at the Battle of Cutanda. He promulgated the fuero of tortum per tortum, facilitating taking the law into one's own hands, which among others reassumed the Muslim right to dwell in the city and their right to keep their properties and practice their religion under their own jurisdiction as long as they maintained tax payment and relocated to the suburbs.
In 1119, he retook Cervera, Tudejen, Castellón, Tarazona, Ágreda, Magallón, Borja, Alagón, Novillas, Mallén, Rueda, Épila and populated the region of Soria. He began the siege of Calatayud, but left to defeat the army at Cutanda trying to retake Zaragoza. When Calatayud fell, he took Bubierca, Alhama de Aragón, Ariza, and Daroca (1120). In 1123, he besieged Lleida, which was in the hands of the count of Barcelona. From the winter of 1124 to September 1125, he was on a risky expedition to Peña Cadiella deep in Andalusia.
In the great raid of 1125, he carried away a large part of the subject Christians from Granada, and in the south-west of France, he had rights as king of Navarre. From 1125 to 1126, he was on campaign against Granada, where he was trying to install a Christian prince, and Córdoba, where he got only as far as Motril. In 1127, he reconquered Longares, but simultaneously lost all his Castilian possessions to Alfonso VII. He confirmed a treaty with Castile the next year (1128) with the Peace of Támara, which fixed the boundaries of the two realms.
He conquered Molina de Aragón and populated Monzón in 1129, before besieging Valencia, which had fallen again upon the Cid's death.
He went north of the Pyrenées in October 1130 to protect the Val d'Aran. Early in 1131, he besieged Bayonne. It is said he ruled "from Belorado to Pallars and from Bayonne to Monreal."
At the siege of Bayonne in October 1131, three years before his death, he published a will leaving his kingdom to three autonomous religious orders based in Palestine and politically largely independent – the Knights Templars, the Hospitallers, and the Knights of the Holy Sepulchre, whose influences might have been expected to cancel one another out. The will has puzzled some historians, who have read it as an unusual gesture of extreme piety, though not out of line with his purported devotion for militant Christianity. Elena Lourie (1975) suggested instead that it was Alfonso's attempt to neutralize the papacy's interest in a disputed succession – Aragon had been a fief of the papacy since 1068 – and to fend off Urraca's son from her first marriage, Alfonso VII of Castile, for the papacy would be bound to press the terms of such a pious testament. Generous bequests to important churches and abbeys in Castile had the effect of making the noble churchmen there beneficiaries who would be encouraged by the will to act as a brake on Alfonso VII's ambitions to break it – and yet among the magnates witnessing the will in 1131 there was not a single cleric. In the event it was a will that his nobles refused to carry out – instead bringing his brother Ramiro from the monastery to assume royal powers – an eventuality that Lourie suggests was Alfonso's hidden intent.