Jaime I of Aragon was born in Montpellier, on February 2, 1208 and died in Alcira, on July 27, 1276. He was a king of Aragon (1213-1276), of Valencia (1239-76) and of Majorca (1229-1276); also count of Barcelone (1213-1276), master of Montpellier (1219-1276) and of other fiefs in Occitania.
     Son of Pedro II the Catholic and of Maria de Montpellier, he was the heir of two important lineages: the House of Aragon and emperors of Byzantium, on the part of his mother.
      He had a difficult infancy. His father, who would end up by repudiating the queen, only went conceivd him by means of trick of some noblemen and ecclesiastics who were afraid for the absence of a successor, and the Maria's collaboration, making to believe Pedro who was going to bed with one of his lovers. These circumstances produced the rejection of Pedro II towards small Jaime, whom did not meet but two years after his birth. At this age, the king did a matrimonial agreement to deliver his son Jaime to the Simón tutelage, master of Montfort, to marry him with the daughter of this, Amicia, for which the child was going to be imprisoned in the Carcasona castle up to 18 years.
      To the death of his father, during the Albigensian crusade, in the battle of Muret (1213), Simón de Montfort refused to deliver Jaime to the Aragoneses even after a year of claims and only for order of pope Inocencio III. During his minority, he was under the tutelage of the templars gentlemen in the Monsoon castle, having been entrusted to Guillem de Mont-Rodon, together with his cousin of the same age, the Count of Provence Ramón Berenguer V. While, was acting like regent of the kingdom count Sancho Raimúndez, son of Petronila of Aragon and Ramón Berenguer IV and Jaime's great-uncle. He inherited the dominion of Montpellier to the death of his mother (1213). Orphan of father and mother, he was approximately 6 years old when was sworn in the Spanish Parliament of Lerida of 1214. In September, 1218 there were celebrated for the first time in Lerida a few general Spanish Parliament of Aragoneses and Catalans, in which he was declared adult.
     In February, 1221 he was married with Leonor of Castile, sister of Mrs Berenguela and aunt of Fernando III of Castile. Annulled his first wedding because of kinship, contracted the second marriage with the princess Violante (September 8, 1235), daughter of Andrés II, king of Hungary. For the testament of his cousin Nuño Sánchez, he inherited the counties of Roussillon and Cerdaña and the Fenolledas viscountcy in France (1241).
     During the first fifteen years of his reign, he supported diverse struggles against the Aragonese nobility, whom did even prisoner to him in 1224. In 1227 he confronted a new Aragonese nobiliary lift directed by the infante Fernando, uncle of the king, who ended, thanks to the papal intervention across the archbishop of Tortosa, with the signature of the concord of Alcala (March, 1227). This agreement marked the victory of the monarchy on the turbulent noblemen, giving him the necessary stability to initiate the campaigns against the Muslims. This stability achieved the pacification of the claims of the nobility.
     In the reign of Jaime I, emphasize the following conquests:
- Conquest of Majorca: 1229
- Conquest of Minorca: 1231 (1287 treated of Capdepera)
- Conquest of Ibiza and Formentera: 1235
- Conquest of Valencia: 1232-1245
- Conquest of the kingdom of Murcia: 1265-66

     From his ultra-pyrenees politics, emphasizes the agreement of Corbeil (1258) by means of which Jaime finished the pretensions on Occitania of the ancient counts of Barcelone. In compensation, San Luis of France was resigning from its rights, as descendant of Carlomagno, on the Catalan counties, hereditary of the Hispanic Mark.
     In September, 1269 he left of Barcelona with his navy for an expedition to Holy Land, but dispersed his ships for the thunderstorms, had to disembark in Aigües-Mortes, near Montpellier, and had to resign that venture.
      After a reign of sixty three years, he died in Alcira (Valencia) on July 27, 1276. At his death's door, in the real residence of this city, and since he had provided, Don Jaime was shrouded with the habits of the císter. The mortal remains of the king remained deposited in Santa Maria of Valencia until May, 1278, in which they were moved to the Poblet monastery for his definitive grave. Nevertheless, after the Mendizábal confiscation, the monastery remained godforsaken and the corpse of Jaime I was moved in 1843 to Tarragona, where a pantheon was constructed him in the back part of the cathedral, which was inaugurated in 1856. In 1952, the remains of Jaime I were returned to Poblet.
     From his first wife, Leonor, he had don Alfonso (1229-1260). He married Constance of Moncada.
     


     From the second, Violante de Hungría, had to:
- Don Pedro (future Pedro III El Grande), who happened to him in the kingdoms of Aragon, Valencia and in the Catalan counties.
- Don Jaime (future Jaime II of Majorca), who inherited the kingdom of Majorca, which was comprising the Balearic Islands -Majorca, Minorca (still under the power of a sovereign Muslim although would pay from 1231), Ibiza and Formentera-, the counties of the Roussillon and the Cerdaña and the territories that the Conqueror was preserving in Occitania (the dominion of Montpellier, the viscountcy of Carlades, in Auvergne, and the barony of Omelades, contiguous to Montpellier).
- Don Fernando (1245-1250), who died being a child.
- Don Sancho (1250-1275), archdeacon of Belchite, abbot of Valladolid and archbishop of Toledo, died prisoner of the Granada Moors.
- Mrs Violante de Aragón (1236-1301), wife of Alfonso X El Sabio.
- Mrs Constanza (1239-1269), wife of the Castilian infante Don Manuel, brother of Alfonso X El Sabio.
- Mrs Sancha, who was a nun and died in Jerusalem.
- Mrs Maria (1248-1267), religious also.
- Mrs Elizabeth (1247-1271), wife of Felipe III the El Atrevido, son of San Luis of France.