The spiritual man judges all things and he himself is judged by no man. ~ 1 Corinthians 2:15, The Bible
Rejecting the Gelasian doctrine of equilibrium, inveterate political meddler Pope Boniface VII went for broke at the end of the 13th century by claiming the supremacy of the church over the state. It won a small concession, but otherwise backfired.
In return for recognizing his title to become Holy Roman Emperor, Albert I of Germany bent his knee to papal consent. France and England were not so pliant.
Boniface’s boldfaced power grab was a guise for money grubbing. The church, like every ambitious great power, consumed prodigious quantities of not-so-filthy lucre. Its financial needs conflicted with those of nascent national monarchies, especially France and England, which were building expensive central administrations over the patchwork feudal system.
In 1296, Boniface declared that laymen had no jurisdiction over the clergy (“over the persons and goods of ecclesiastics”) without prior papal permission. No mundane authority could levy taxes on church property, nor were clergy permitted to pay them. The sanction for such action was excommunication.
Both France and England, to which the papal bull was particularly targeted, would not countenance a financial state within a state. Without tax sovereignty, political sovereignty was meaningless. More to the point, church property was so vast that tax exemption was beyond what either monarchy could afford.
King Edward I of England threatened that the king’s peace could not be had for nothing. If the clergy were to refuse taxes, he would consider them outcasts, and treat them as such. Boniface had to give in. The principle was never mentioned again.
King Philip IV rejected out of hand Boniface’s interference in French finances. The pope was powerless to enforce his edict.
One sword ought to be subordinated to the other, and temporal authority subjected to spiritual power. ~ Pope Boniface VII in the papal bull Unam Sanctam (1302)
Boniface was not finished lording it over royalty. In declaring “that it is altogether necessary of salvation for every human creature to be subject to the Roman Pontiff,” Boniface brandished his sword.
Philip IV accepted the challenge thrust at him. Having been excommunicated, Philip planned to bring Boniface to dock before the church in France over 29 charges, including heresy, murder, sexual immorality, magic, and idol worship.
With fulminations bouncing back and forth, Philip decided to resolve the dispute with a coup. He sent a small force to kidnap the pope and bring him back to France to be tried, condemned, and deposed.
Though seized in Italy, Boniface was saved by local revulsion against the plot. Boniface returned to Rome, where he died a few weeks later from the shock and stress of being held under duress.
Boniface’s power play ended up undermining universal authority: first of the emperor, then of the papacy itself. In going up against England and France, Boniface challenged the strongest political institution of the future: the sovereign nation-state. By diminishing belief in universality, Boniface unknowingly abetted the growth of separatist nationalism, as well as inspiring hostility against the church itself for his high-handed antics.
The following year, a French archbishop was elected pope. Clement V cleaned up the mess Boniface left by annulling all pronouncements against Philip and his advisors, including those who kidnapped Boniface.
Clement V did not go to Rome. Instead he set up his court in Avignon, in southern France, where he and his 6 successors, all French, resided.