Bertrand was canon and sacristan of the church of Saint-André in Bordeaux, then vicar-general to his brother, the archbishop of Lyons, who in 1294 was created Cardinal Bishop of Albano. He was then made bishop of St-Bertrand-de-Comminges, the cathedral church of which he was responsible for greatly enlarging and embellishing; and chaplain to Boniface VIII, who made him archbishop of Bordeaux.
He was elected in June 1305, after a year's interregnum occasioned by the disputes between the French and Italian cardinals, who were nearly equally balanced in the conclave, which had to be held at Perugia. Bertrand was neither Italian nor a cardinal, and his election might have been considered a gesture towards neutrality. The contemporary chronicler Giovanni Villani reports gossip that he had bound himself to king Philip IV of France by a formal agreement previous to his elevation, made at St. Jean d'Angly in Saintonge. Whether this was true or not, it is likely that the future pope had conditions laid down for him by the conclave of cardinals. At Bordeaux, Bertrand was formally notified of his election and urged to come to Italy; but he selected Lyons for his coronation, November 14, 1305, which was celebrated with magnificence and attended by Philip, and among his first acts was the creation of nine French cardinals.
Early in 1306, Clement explained away those features of the bulls Clericis Laicos that might seem to apply to the king of France and essentially withdrew Unam Sanctam, the two bulls of Boniface which were particularly offensive to Philip's ambitious ministry. He appears to have conducted himself throughout his pontificate as the mere tool of the French monarchy, a radical change in papal policy.
On October 13, 1307 came the arrest of all the Knights Templar in France, an action apparently financially motivated and undertaken by the efficient royal bureaucracy to increase the prestige of the crown. Philip was the encouraging patron of this ruthless move, but the historical reputation of Clement, has also been tarnished. From the very day of Clement's coronation, the king had charged the Templars with heresy, immorality and abuses, and the scruples of the pope were compromised by a growing sense that the burgeoning French State might not wait for the Church, but would proceed independently.
In March 1309 the entire papal court settled at Avignon, which at the time was not part of France, but an imperial fief held by the king of Sicily. The removal of the Papacy to Avignon was justified at the time by French apologists as owing to the factious tumults at Rome, where the dissensions of the Roman aristocrats and their armed gangs reached a nadir, and the Basilica di San Giovanni in Laterano was destroyed in a fire, but it proved the precursor of the long Avignon Papacy, the 'Babylonian captivity', in Petrarch's phrase, and marks the point from which the decay of the strictly Catholic conception of the Pope as universal bishop is to be dated.
Meanwhile, Philip's lawyers pressed to reopen Nogaret's charges of heresy against the late Boniface VIII, that had circulated in the pamphlet war around Unam sanctam. Clement had to yield to pressures for this extraordinary trial, begun February 2, 1309 at Avignon, which dragged on for two years. In the document that called for the witnesses, Clement expressed his personal conviction of the innocence of Boniface, at the same time his resolution to satisfy the king. Finally, in February, 1311, the king wrote to Clement abandoning the process to the future council of Vienne. For his part, Clement absolved all the participants in the abduction of Boniface at Anagni.
In pursuance of the king's wishes Clement summoned the Council of Vienne (1311), which would not conclude that the Templars were guilty of heresy. The pope abolished the order anyway, as it seemed to be in bad repute and had outlived its usefulness as Papal bankers and protectors of pilgrims in the East. Its French estates were granted to the Knights Hospitallers, but actually Philip IV held them until his death and expropriated the Templar's bank outright.
Charges of heresy and sodomy aside, the guilt or innocence of the Templars is one of the more difficult historical problems, partly because of the atmosphere of hysteria that had built up in the preceding generation, the habitually intemperate language and extravagant denunciations exchanged between temporal rulers and churchmen, and partly because the subject has been embraced by conspiracy theorists and pseudo-historians.
Cement's pontificate was also a disastrous time for Italy. The Papal States were entrusted to a team of three cardinals, but Rome, the battleground of the Colonna and Orsini factions, was ungovernable. In 1312, the Emperor Henry VII entered Italy, established the Visconti as vicars in Milan, and had himself crowned by Clement's legates in Rome before he died near Siena in 1313.
In Ferrara, Papal armies clashed with Venice. When excommunication and interdict failed to have their intended effect, Clement preached a crusade against the Venetians, a symptom of how debased that particular coinage had become.
Other remarkable incidents of Clement's reign are his bloody repression of the heresy of Fra Dolcino in Lombardy and his promulgation of the Clementine Constitutions in 1313. He died in April 1314. According to one story, while his body was lying in state, a thunderstorm developed during the night and lightning struck the church ,where his body was, and it ignited the building. The fire was so intense that, when it was extinguished, the body of Pope Clement was almost completely destroyed. He is buried at La Chaise-Dieu in Auvergne.
Clement V is often remembered for his nepotism, avarice, weakness and cunning, and often vilified as a willing collaborator in the designs of France against the Pope, who ushered in a century of schism: in the Divine Comedy, written while the pope was alive, Dante is shown the place which awaits Clement in the eighth circle of Hell. He is recorded as the first pope to be crowned with a papal tiara.