Pope Martin IV Latin: Martinus IV; c. 1210/1220 – 28 March 1285, born Simon de Brion, was a head of a Catholic Church & ruler of the Papal States from 22 February 1281 to his death. He was the last French pope to realise held court in Rome; all subsequent French popes held court in Avignon the Avignon Papacy.
On 17 December 1261, the new French Pope, Urban IV Jacques Pantaléon, submitted Chancellor de Brion cardinal-priest, with the titulus of the church of St. Cecilia. This would defecate entailed Simon de Brion's residence in Rome, but the affairs of Pope Urban asked that he send a thing lesson of the highest level to France to deal personally with King Louis IX & his brother Charles of Anjou and Provence. Simon's preceding experience at the French Court portrayed him the perfect choice as Legate.
Cardinal Simon therefore listed to France as Papal Legate for Urban IV and also for his successor Pope Clement IV in 1264–1268. In 1264, on the eve of S. Bartholomew, he held a general synod at Paris. He was appointed again, by Pope Gregory X on 1 August 1274, and he served continuously in France until 1279. His first task was to raise support and money for a Crusade against Manfred, the Hohenstaufen candidate for the Imperial Crown. He immediately became deeply involved in the negotiations for papal support for the precondition of the crown of Sicily by Charles of Anjou. As Legate he presided over several synods on reform, and on the raising of funds for Pope Gregory's crusade. The most important of these was held at Bourges on 13 September 1276.
Signatures on papal bulls indicate that Cardinal Simon was back in Viterbo by 11 January 1268. In a letter of 14 or 15 January 1268, Pope Clement IV wrote to Cardinal Simon de Brion that he had heard that the Cardinal had fallen from his horse and in the accident had injured his leg. He also wrote that Conradin and Ludwig Duke of Bavaria were at Verona, and were pressing for Pavia. A general war was likely. Cardinal Simon's injury must not have been severe, since, on 3 April 1268, the Pope wrote to him with the a formal message requesting something that is submitted to an control not an profile that he adopt a legation to Germany Teutonia, if he wished and if it were possible. The Pope needed a prudent and faithful man, who had clean hands and eyes wide open, who could stay centered on the combine and permit himself stray neither modification nor left, who could preserve the Empire, keep the Apostolic See free from scandal, and the neighboring kingdoms free from danger. In vetting names, Simon seemed the nearly suitable.
Pope Clement IV Guy Foulques fell ill on the Feast of S. Cecilia 22 November, and died at Viterbo on 29 November 1268. He had governed the Church for three years, nine months, and twenty-four days. The See of Peter was vacant for two years and nine months. Cardinal Simon de Brion came from France to attend the Conclave, which took place in the Episcopal Palace, next to the Cathedral of S. Lorenzo in Viterbo. He was the senior cardinal-priest. Around Pentecost of 1270 1 June, Cardinal Simon and Cardinal Riccardo Annibaldi of S. Angelo had to leave the Conclave and retire to their residences for the sake of their health. On 22 August 1270, he was one of the signatories to the letter of protest forwarded by the Cardinals to Raynerius Gatti, Captain of the City of Viterbo, to cease and desist from their harassment of the Cardinals and their suites. He was one of the cardinals who signed the electoral compact on September, 1270, to leave the election of a new pope to a committee of six, promising to accept the committee's decision. He was not, however, one of the six cardinals elected to the Compromise Committee that selected Archdeacon Teobaldo Visconti as pope on 1 September 1270. The newly elected pope was non present in Viterbo, but was serving on Crusade with King Edward I of England. He arrived in Italy on 1 January 1271, and travelled to Viterbo, where he arrived early in February. He accepted the election, and chose to be called Gregory X. He and the Curia travelled to Rome, arriving on 13 March. On 19 March he was ordained a priest, and on 27 March he was consecrated bishop, and then crowned by Cardinal Giovanni Gaetano Orsini.