The Sun and Moon Allegory

Pope Innocent III was determined to assert papal authority over every area possible. He made sure that kings, although they had their "local" political power, were still under the spiritual authority of the pope. Elected in January 1198, in November of that year he wrote a letter laying out something called the "Sun and Moon allegory":

Just as God, founder of the universe, has constituted two large luminaries in the firmament of Heaven, a major one to dominate the day and a minor one to dominate the night, so he has established in the firmament of the Universal Church, which is signified by the name of Heaven, two great dignities, a major one to preside—so to speak—over the days of the souls, and a minor one to preside over the nights of the bodies. They are the Pontifical authority and the royal power. Thus, as the moon receives its light from the sun and for this very reason is minor both in quantity and in quality, in its size and in its effect, so the royal power derives from the Pontifical authority the splendour of its dignity...

In the Fourth Lateran Council, called by Innocent in 1215, this philosophy was enshrined in Canon 3:

... if a temporal ruler, after having been requested and admonished by the Church, should neglect to cleanse his territory of this heretical foulness, let him be excommunicated by the metropolitan and the other bishops of the province. If he refuses to make satisfaction within a year, let the matter be made known to the supreme pontiff, that he may declare the ruler's vassals absolved from their allegiance and may offer the territory to be ruled by Catholics, who on the extermination of the heretics may possess it without hindrance and preserve it in the purity of faith; the right, however, of the chief ruler is to be respected as long as he offers no obstacle in this matter and permits freedom of action.

The Church was perfectly happy to leave the temporal authorities to do whatever they liked, so long as nothing they did contradicts or offended the laws of the Church.

Pope Boniface VIII (1294 - 1303) issued the papal bull Unam Sanctam ("One Faith") reinforcing this approach to the two estates. Dante argued against this, stating that emperor and pope each has supreme authority in their sphere, but neither is allowed to influence the other. By the end of the 14th century, belief in the pope's authority to meddle in secular matters was waning.

But in Innocent's time, he used it frequently. We'll get into specifics tomorrow.

One Faith

When Pope Boniface VIII wasn't excommunicating people for treating corpses in unapproved ways, he was very busy doing lots of other things.

Maybe we should start at the beginning.

Benedetto Gaetani was born about 1235 in Italy. A younger son of minor nobility, his religious career began when he was sent to a monastery. He became secretary to a cardinal in 1264, which put him close to Vatican politics. He had a busy career in international affairs, accompanying a cardinal to England to put down a rebellion, going to France to supervise a collection, and acting as a diplomat to France, Naples, Sicily and Aragon.

In December of 1294, stating "the desire for humility, for a purer life, for a stainless conscience, the deficiencies of his own physical strength, his ignorance, the perverseness of the people, his longing for the tranquility of his former life," Pope Celestine V resigned. A contemporary said that it was Benedetto Gaetani who convinced him to resign; other reports say that he was only one of several, or that Gaetani was the person who convinced Celestine that a papal resignation was legal. Whatever the case, Benedetto Gaetani was elected pope by the conclave on Christmas Eve.

That's when the fun began. His first act was to imprison his predecessor. A few years later he formalized the Roman Jubilee, a tradition that established a year of pilgrimages to Rome for pardoning of sins. This influx of tourists seeking forgiveness turned into a big money-maker for the pontiff. This may be why Dante put Boniface into the 8th circle of Hell in Inferno, with the simonists. He enriched the lives of his relatives, and used his position to war against the Colonna family (rivals of the Gaetani); he even offered a pardon for one's sins equivalent to that granted when one goes on Crusade if you would join in his war against the Colonna. He was the epitome of a power-mad ruler.

Then, on 18 November 1302, Boniface made his boldest move: the papal bull called Unam Sanctam (One Faith). The document establishes that salvation is only available through the Church, and that the Church wields "two swords" that represent both spiritual and temporal power. Among other pronouncements, it concludes with

Furthermore, we declare, we proclaim, we define that it is absolutely necessary for salvation that every human creature be subject to the Roman Pontiff.

...and that has been the source of endless conflict between the papacy and others ever since.