A change in the papacy immensely strengthened Winchelsea’s position against Edward.  In December, 1294, Celestine, overpowered with the burden of an office too heavy for his strength, made his great renunciation and sought to resume his hermit life.  The Cardinal Benedict Gaetano was at once elected his successor and took the style of Boniface VIII.  The son of a noble house of the neighbourhood of Anagni, a canonist, a politician, and a zealot, the new pope had made personal acquaintance with Edward and England from having attended Cardinal Ottobon on his English legation, and was eager to appease discord between Christian princes in order to forward the crusade.  He hated war the more because it was largely waged with the money drawn from the clergy, and was indignant that the custom of taxing the Church, which was begun under the guise of crusading tenths, had become so frequent that both Philip and Edward applied it in order to raise revenue from ecclesiastics for frankly secular warfare.  Within a few weeks of his accession he despatched two cardinals to mediate peace between the Kings of France and England, and was disgusted at the long delays with which both kings had sought to frustrate his intervention.  On February 29, 1296, Boniface issued his famous bull Clericis laicos, in which he declared it unlawful for any lay authority to exact supplies from the clergy without the express authority of the apostolic see.  Princes imposing, and clerics submitting to such exactions were declared ipso facto excommunicate.

Boniface’s contention had been urged by his predecessors, and it is improbable that he sought to do more than assert the ancient law of the Church and save the clergy all over the Latin world from exactions which were fast becoming intolerable.  His object was quite general, though a pointed reference to the extortions of Edward in 1294 showed that he had the case of England before his mind.  He had no wish to throw down the gauntlet to the princes of Christendom, or to quarrel with Edward and Philip, between whom he was still conducting negotiations.  It was his misfortune that he was constantly forced to face fresh conditions which rendered it almost possible to apply the ancient doctrines.  Strong national kings, like Edward and Philip, had already shown impatience with such traditions of the Church as limited their temporal authority.  The pope’s untimely restatement of the theories of the twelfth century at once involved him in his first fierce difference with Philip the Fair, and put him into a position in which he could only win peace by explaining away the doctrine of Clericis laicos.  While on the continent the conflict of Church and State took the form of a dispute between the French king and the papacy, in England it assumed the shape of a struggle between Edward and the Archbishop of Canterbury.