Although the attack on Constantinople went against his explicit orders, and the Crusaders were subsequently excommunicated, Innocent reluctantly accepted this result, seeing it as the will of God to reunite the Latin and Eastern Orthodox Churches.

In the event, the sack of Constantinople and the subsequent period of Frankokratia heightened the hostility between the Latin and Greek churches; the Byzantine Empire was restored in 1261, albeit in a much weaker state.

[13] In 1198, Innocent wrote to the prefect Acerbius and the nobles of Tuscany expressing his support of the medieval political theory of the sun and the moon.

For similar reasons he annulled, in 1208, the marriage of the crown-prince, Afonso II of Portugal, with Urraca, daughter of Alfonso of Castile.

This determination meant, among other things, that princes should not be involved in the selection of bishops, and it was focused especially on the "patrimonium" of the papacy, the section of central Italy claimed by the popes and later called the Papal States.

Emperor Henry VI expected his infant son Frederick to bring Germany, Italy, and Sicily under a single ruler, which would leave the Papal States exceedingly vulnerable.

[3] Innocent was concerned that the marriage of Henry VI and Constance of Sicily gave the Hohenstaufens a claim to all the Italian peninsula with the exception of the Papal States, which would be surrounded by Imperial territory.

...On the foregoing grounds, then, we decide that the youth should not at present be given the empire; we utterly reject Philip for his manifest unfitness and we order his usurpation to be resisted by all ... since Otto is not only himself devoted to the church, but comes from devout ancestors on both sides, ... therefore we decree that he ought to be accepted and supported as king, and ought to be given the crown of empire, after the rights of the Roman church have been secured.

"Papal Decree on the choice of a German King, 1201"[18] The confusion in the Empire allowed Innocent to drive out the imperial feudal lords from Ancona, Spoleto and Perugia, who had been installed by Emperor Henry VI.

[19] On 3 July 1201, the papal legate, Cardinal-Bishop Guido of Palestrina, announced to the people, in the cathedral of Cologne, that Otto IV had been approved by the pope as Roman king and threatened with excommunication all those who refused to acknowledge him.

This decree was afterwards embodied in the Corpus Juris Canonici and contained the following items: Despite papal support, Otto could not oust his rival Philip before the latter was murdered in a private feud.

His rule now undisputed, Otto reneged on his earlier promises and set his sights on reestablishing Imperial power in Italy and claiming even the Kingdom of Sicily.

[20] The conflict was decided by the Battle of Bouvines on 27 July 1214, which pitted Otto, allied to King John of England against Philip II Augustus.

[21] At the request of England's King John, Pope Innocent III declared Magna Carta annulled, which resulted in a rebellion by the English barons who rejected the disenfranchisement.

[24][25] Unlike past popes, Innocent III displayed interest in leading the crusade himself, rather than simply instigating it and allowing secular leaders to organize the expedition according to their own aspirations.

[26] Innocent III's first order of business in preaching the crusade was to send missionaries to every Catholic state to endorse the campaign.

He sent Peter of Capua to the kings of France and England with specific instructions to convince them to settle their differences, resulting in a truce of five years between the two nations, beginning in 1199.

[29] Innocent gave his approval of this agreement under two conditions: a representative of the pope must accompany the crusade, and the attack on any other Christians was strictly forbidden.

During the first year of his pontificate, Innocent sent the two Cistercian monks Rainer and Guido to the Albigenses in France to preach to them the true doctrines of the Catholic faith and dispute with them on controverted topics of religion.

The two Cistercian missionaries were soon followed by Diego, Bishop of Osma, then by Saint Dominic and the two papal legates, Peter of Castelnau and Raoul.

Under the leadership of Simon de Montfort a cruel campaign ensued against the Albigenses which, despite the protest of Innocent, soon turned into a war of conquest.

[3] During the siege of Béziers, the leader of the crusader assault famously but dubiously declared upon being asked how to distinguish Cathars from Catholics at the besieged town "Caedite eos.

[26] The conflict took on a political flavor, directed not only against the heretics, but also the nobility of Toulouse and vassals of the Crown of Aragon, and finally brought the region firmly under the control of the king of France.

In 1209, Francis of Assisi led his first eleven followers to Rome to seek permission from Pope Innocent III to found a new religious order which was ultimately granted.

[35] Upon entry to Rome, the brothers encountered Bishop Guido of Assisi, who had in his company Giovanni di San Paolo, the Cardinal-Bishop of Sabina.

[36] This was important in part because it recognized Church authority and protected his followers from possible accusations of heresy, as had happened to the Waldensians decades earlier.

[37] The lesser religious orders which Pope Innocent III approved are the Hospitallers of the Holy Ghost on 23 April 1198, the Trinitarians on 17 December 1198, and the Humiliati, in June 1201.

[3] Innocent is one of two popes (the other being Gregory IX) among the 23 historical figures depicted in marble relief portraits above the gallery doors of the U.S. House of Representatives in honor of their influence on the development of American law.