Pedro De Luna, a Spanish ecclesiastic, anti-pope under the name of Benedict XIII., born in Aragon in 1334, died in Peniscola, Valencia, in 1424. He belonged to an old family of Spanish grandees, and devoted himself at first to the study and teaching of jurisprudence. He was made a cardinal by Gregory XL, and the antipope Clement VII. appointed him legate to Paris in order to cause Charles VI. to resist the dictum of the Paris university that both popes of that time, Clement VII. of Avignon and Boniface IX. of Rome, should resign. After Clement's death in 1394 the cardinals of Avignon elected Luna as his successor, on the condition that he should labor to quell the schism, and should resign the papal dignity whenever the pope of Rome should do the same, or the college of cardinals demand it. Luna, however, once pope, only furthered the widening of the schism, and when called upon to lay down the tiara firmly refused, whereupon it was finally agreed in a council held at Paris in 1398 to refuse obedience to him.

Charles VI. attempted to compel him to resign by keeping the town of Avignon for several years in a state of siege; but Luna escaped, and in 1403, popular sentiment being again in his favor, he was recognized as the legitimate pope by France, Castile, Portugal, and Sicily. It was discovered, however, that Luna himself would do nothing to restore the unity of the church, and hence in 1407 he was again refused obedience. Luna put the disobedient under ban; but at length the council of Pisa in 1409 deposed both him and Gregory XII., and elected Alexander V. Aragon, Castile, and Scotland, however, continued to give him their support till, refusing to resign in obedience to the council of Constance, he was deposed July 26, 1417, and forsaken by the powers that had hitherto supported him. He shut himself up in the fortress of Peniscola, where he held out obstinately till his death.