Polo, who was then 17 years old) returned to the Mongol Empire and remitted the oil from the Pope to Kublai in 1275. The Mongol Ilkhanate leader Abaqa sent a delegation with over a dozen members to the 1274 Council of Lyon, where plans were made for possible military cooperation between the Mongols and the Europeans. After the Council, Abaqa sent another embassy led by the Georgian Vassali brothers to further notify Western leaders of military preparations. Gregory X answered that his legates would accompany the Crusade, and that they would be in charge of coordinating military operations with the Il-Khan. However, these projects for a major new Crusade essentially came to a halt with the death of Gregory X on 10 January 1276. The money which had been saved to finance the expedition was instead distributed in Italy. Pope and Council Sometime during his reign as pope, Gregory X wrote a letter against the charges of "blood libel" and persecution against the Jews. Mindful of the scandals attached to the conclave at Viterbo that had elected him, realizing that tighter controls on the entire process of election were needed, he produced the papal bull "Ubi periculum" which was subsequently ratified by the Council of Lyons on 16 July 1274 and incorporated into the Code of Canon Law. On his arrival at Rome in 1272, his first act was to carry forward the wish of Gregory IX and summon a council. Two days after his coronation Gregory X sent a letter to King Edward I of England, inviting him to a general council to be held on the subject of the Holy Land, beginning on 1 May 1274. Pope Gregory X left Orvieto on 5 June 1273, and arrived in Lyons in the middle of November 1273. Not all of the cardinals followed him. Pope Gregory notes in a letter to King Edward dated 29 November 1273 that Cardinal Riccardo Annibaldi and Cardinal Giovanni Orsini were still in Rome and had been ordered to find a secure place of imprisonment for Guy de Montfort. The two cardinals were hereditary enemies and would be an effective check on each other. Neither was present at the opening of the Council of Lyons. Gregory himself had an immediate meeting with King Philip III of France, whom he had been cultivating vigorously since his accession. The meeting was evidently quite harmonious and successful, since