Pedro III of Aragon was born in Valencia, in 1240 and died in Villafranca del Penedés, on November 2, 1285. He was called "The big", being son of Jaime I the Conqueror and his second wife Violante de Hungría. He was the successor of his father in 1276 in the king of Aragon, king of Valencia (like Peter I) and count of Barcelone (like Pedro II).
     He was married on June 13, 1262 in the cathedral of Montpellier with Constance of Hohenstaufen, daughter and heiress of Manfredo I of Sicily, they were crowned in Saragossa in a ceremony in which Pedro cancelled the vassalage that with the papacy his grandfather Pedro II had coordinated.
      All his reign was centred on the expansion of the Crown of Aragon for the Mediterranean and for it he made use of his marriage with Constance to claim the Sicilian crown. Sicily was from 1266 under the sovereignty of Carlos de Anjou who, with the support of pope Clemente IV, who was not wishing any Hohenstaufen in the south of Italy, had been invested king after defeating, in Benevento to Manfredo, who died in the battle.
     The angevin monarch made to blind to three Manfredo's children males and, in 1268, captured and made to decapitate to Conradino that -like grandson of Federico II- was the last hereditary male of the house Hohenstaufen. The succession line goes then to Constance, who offered refuge in Aragon to the supporters families of her father, the Lanza, the Lauria and the Prócidas.
     A fleet of the Aragonese crown, supervised by Conrado Lanza, covers in 1279 the African coasts to restore the feudal sovereignty of Aragon on Tunisia, that the death of the emir Muhammad I al-Mustansir had debilitated. Later, in 1281, Pedro III armed a fleet to invade Tunisia and requested newly elected pope Martín IV a bull that the military operation was declaring like crossed; but the pope, of origin French and supporter of Carlos de Anjou, denied it to him.
     When the fleet was preparing to weigh anchor, would took place in Sicily the events known like "Sicilian day before" that provoked the expulsion of the island, after a big slaughter, of the French. The Sicilian sent then an embassy to Pedro III offering him the Sicilian crown, to which had a right thanks to his marriage. The Aragonese king put then his fleet in the direction of Sicily, where arrived on August 30, 1282 and where king was crowned in the city of Palermo. Immediately he sent an embassy to Carlos de Anjou, who was in Messina, urging him to admit him as a king of Sicily and to leave the island. The defeat of the angevin fleet in Nicoreta, in hands of admiral Roger de Lauria, forced Carlos to leave Messina and to shelter in his kingdom of Naples. Pope Martín IV answered to the Sicilian coronation of Pedro III with his excommunication (November 9, 1282) and his deposition like king of Aragon (December 21, 1283), offering the crown to the second son of the king of France, Carlos de Valois, whom invested on February 27, 1284, and declaring a crusade against Aragon.
     The situation of Pedro III was completely unstable, since not only he had face up to the French invasion that was prepared to the north of the Pyrenees, but he had face up to serious problems inside his kingdoms arisen by the economic needs that the conquest of Sicily provoked.
      Pedro III the Big solves the internal problems granting, in 1283, the formation of the Aragonese Union and taking an oath to the "General Privilege" that was defending the privileges of the nobility; also he granted to the County of Barcelona the constitution “Una vegada l´any” in the courts celebrated in Barcelona between 1283 and 1284.
     Solved the interior problems, he could center his attention on the French invasion, which supervised by the proper French king Felipe III took in 1285 the city of Gerona, for immediately having to move back when the Aragonese fleet returned of Sicily supervised by Roger de Lauria and inflicted on the French squadron an entire defeat in the Formigues islands and next a defeat in ground in the ravine of the Panizas, when the French troops were moving back.
     After his big victory, Pedro III prepared to confront with his brother Jaime II and his nephew the king Sancho IV of Castile, who had not given him support during his conflict with the French, but his premature death, in November, 1285, prevented it.

     In his testament, Pedro III arranged that his corpse was receiving grave in the Monastery of Santes Creus, of the Cistercian order. The funeral of the monarch was celebrated by big solemnity and the body of the king was placed in an urn of red porphyry, that admiral Roger de Lauria brought from Sicily. He was the first Aragonese monarch in receiving grave in the Monastery of Santes Creus. King Jaime II the Just of Aragon, arranged the construction of the graves of king Pedro III the Big, his father, at the same time that he was arranging the creation of his own grave and that of his second wife, Blanca de Nápoles. It was arranged that the tombs were sheltered, as this way was done, under baldachins worked in white marble proceeding from the quarries of San Felíu, near Gerona. When king Jaime II arranged the creation of his own tomb, he took that of his father as a model. The tomb of king Pedro III was realized between the year 1291 and 1307 by Bartomeu of Gerona and it is richer than that of his son Jaime II and wife. A little temple lodges the tomb of the king, consisting of an urn of red porphyry; before a Roman font of bath, surrounded by saints' images.
     In December, 1835, during the Carlists Wars, the French Legion of Alger and several companies of municipal polices stayed at the monastic building, causing numerous ravages in the same. The real graves of Jaime II and his wife were profaned. The remains of Jaime II, son of Pedro III were burned, although it seems that some remains remained in the tomb. The mummy of the queen Blanca de Nápoles was thrown to a well, from which was extracted in 1854. The tomb of Pedro III, by the soundness of the urn of porphyry used to lodge the royal remains, prevented his remains would have equal luck.
     


     His descent is that continues:
- Alfonso III of Aragon (1261-1291), king of Aragon, Valencia and count of Barcelone.
- Jaime II of Aragon (1267-1327), king of Aragon, Valencia, count of Barcelone, king of Sardinia and of Sicily.
- Isabel de Aragón (1271-1336), «Santa Elizabeth of Portugal», spouse queen of Portugal for her marriage in 1288 with Dionysius I of Portugal.
- Federico II of Sicily (1272-1337), king of Sicily
- Violante (1273-1302), married in 1297 with the infante Roberto de Nápoles, who would be future Roberto I.
- Pedro de Aragón (1275-1296).

    He had three illegitimate sons of his extramarital relation with Maria Nicolau:
- Jaime de Aragón (deceased after 1285). Master of Segorbe. Married with Sancha Fernández, daughter of Fernando Díaz.
- Juan de Aragón.
- Beatriz de Aragón, wife of Ramón de Cardona, master of Torá.

     By his relation with Inés Zapata, four illegitimate sons were born:
- Fernando de Aragón. His father gave him the Albarracín dominion in 1284 after besieging and taking the city in September of this year, defeating to Juan Núñez I of Lara.
- Sancho de Aragón. Castellán de Amposta.
- Pedro de Aragón, married Constance Méndez Pelita de Silva, daughter of Suero Méndez de Silva.
- Teresa Pérez Zapata. She contracted three marriages: the first with García Romeu III, rich-man of Aragon, son of García Romeu II; the second with Artal de Alagón, master of Sástago and Pina; and the third with Pedro López de Oteiza.