Guy had been an unlikely candidate for holy orders: widowed and the father of two young women, before taking orders he had been successively a
soldier and a
lawyer, and in the latter capacity had acted as
secretary to
Louis IX of France, to whose influence he was chiefly indebted for his elevation. Upon the death of his wife, he followed his father's example and gave up secular concerns for the Church. His rise in the church was rapid: in
1256, he was
Bishop of Le Puy, in
1259, Archbishop of Narbonne and in December
1261, he was the first cardinal created by
Pope Urban IV (1261–64), in the
see of Sabina. He was the
papal legate in England
1262–1264.
At this time the
Holy See was engaged in a conflict with
Manfred, the illegitimate son and designated heir of
Frederick II of Hohenstaufen, but whom papal loyalists, the
Guelfs, called "the usurper of
Naples". Clement IV, who was in France at the time of his election, was compelled to enter
Italy in disguise. He immediately took steps to ally himself with Charles of Anjou, his erstwhile patron's brother, the impecunious French claimant to the
Neapolitan throne. Charles allowed the Pope to be his
feudal overlord (a bone of contention with the Hohenstaufen) and was crowned by cardinals in Rome, where Clement IV, permanently established at
Viterbo, dared not venture, the
Ghibelline party was so firmly in control. Then, fortified with papal money and supplies, Charles marched into Naples. "Papal legates and mendicant friars appeared upon the scene, preaching a formal crusade, with the amplest indulgences and most lavish promises" (
Catholic Encyclopedia). Among the Italians who failed to see any nobler crusading purpose in the conflict was
Dante (
Inferno, Canto xxvii). Having defeated and slain Manfred in the great
Battle of Benevento, Charles established himself firmly in the kingdom by the conclusive
Battle of Tagliacozzo, in which
Conradin, the last of the house of
Hohenstaufen, was taken prisoner. Clement IV is said to have disapproved of the cruelties committed by his protegé, and there seems no foundation for the statement by
Gregorovius that Clement IV became an accomplice by refusing to intercede for the unfortunate Conradin whom Charles had beheaded in the marketplace of Naples.
Within months Clement IV was dead too, and buried at Viterbo. Owing to unbridgeable divisions among the cardinals, the papal throne remained vacant for nearly three years.
Clement IV's private character was praised by contemporaries for his asceticism, and he is especially commended for his indisposition to promote and enrich his own relatives. He also did himself great honour by his encouragement and protection of
Roger Bacon. He was buried at
Viterbo, where he had resided throughout his pontificate.
In 1264, Clement IV, assigns Talmud censorship committee. He ordered that the Jews of Aragon to submit their books to Dominican censors for expurgation.