Innocent III has since 1208 been planning a crusade in order to destroy the Ayyubid Empire and to recapture Jerusalem.

In April 1213, Innocent issues the papal bull Quia maior, calling all of Christendom to join a new crusade.

John marries Princess Stephanie of Armenia, daughter of the Armenian king Leo II, in 1214.

During the truce with the Ayyubids, he persuades Pope Innocent to launch the Fifth Crusade in support of his daughter's kingdom.

A great many bishops have the opportunity to attend the Fourth Lateran Council due to the great length of time between its convocation and meeting.

The twelfth ecumenical council, it is sometimes called "the General Council of Lateran" due to the presence of seventy-one patriarchs and metropolitan bishops, four hundred and twelve bishops, and nine hundred abbots and priors together with representatives of several monarchs.

The Council confirms the elevation of Frederick II as Holy Roman Emperor.

Despite the unmitigated disaster of the Fourth Crusade, something of the original crusading fervor still obtains in certain areas of society, but there is considerable disillusionment among the nobility, especially when the same religious indulgence has been promised in the “Crusade” against heretics in southern France, as it will be later against secular opponents of the popes.

Innocent, despite his preoccupation with the kings of England and France, a civil war in Germany, heresy, the advance of Islam in Spain, and his strenuous efforts to promote widespread ecclesiastical reform, renews his efforts to organize another expedition to the Holy land.

With the Latin Patriarch of Jerusalem, Raoul of Merencourt, he discusses the recovery of the Holy Land, among other church business.

Pope Innocent wants it to be led by the papacy, as the First Crusade should have been, in order to avoid the mistakes of the Fourth Crusade, which had been essentially hijacked by the Venetians.

Preachers are designated; even troubadours contribute to the propaganda.

The final canon promulgated by the Fourth Lateran Council is an elaborate Crusade plan repeating earlier prohibitions on the transport of military supplies to Muslims.

Levies on clerical incomes are again authorized.

This council—which, like the less important Second and Third Lateran Councils, mandates imprisonment and confiscation of property as punishment for heresy and threatens to excommunicate princes who fail to punish heretics—proscribes the works of Aristotle.

The council also provides additional legal basis for Christian rejection of Jews, ordering Jews and Saracens to wear distinctive dress and requiring Jews in Christian lands to wear a skullcap as a distinguishing mark.

Jews must live in segregated quarters.

Jews may not exact interest on loans to Christians, and Christians may not do business with Jews who do not obey Church rules.

Moreover, Jews may not hold public office; converts to Christianity must stop Jewish observances, and Jews are prohibited from hiring as servants Christian women of childbearing age.

The council sanctions a definition of the Eucharist in which the word transubstantiation is used officially for the first time, and adopts several precepts binding on Roman Catholics, including the Easter duty, or obligation, of annual confession of serious sin followed by Holy Communion.

The Fifth Crusade is an attempt to take back Jerusalem and the rest of the Holy Land by first conquering the powerful Ayyubid state in Egypt.

Pope Honorius III organizes crusading armies led by Leopold VI of Austria and Andrew II of Hungary, and a foray against Jerusalem ultimately leaves the city in Muslim hands.

A German army led by the preacher Oliver of Cologne and a mixed army of Dutch, Flemish and Frisian soldiers led by William I, Count of Holland arrives later in 1218.

In order to attack Damietta in Egypt, they ally with the Seljuq Sultanate of Rûm in Anatolia, whose forces attack the Ayyubids in Syria in an attempt to free the crusaders from fighting on two fronts.

The crusaders, after occupying the port of Damietta, in July of 1221 march south towards Cairo, but are turned back after their dwindling supplies lead to a forced retreat.

A nighttime attack by Sultan Al-Kamil results in a great number of crusader losses and eventually in the surrender of the army.

Al-Kamil agrees to an eight-year peace agreement with Europe.

Pope Innocent III dies on July 16, 1216, having brought the papacy to a pinnacle of political power by successfully developing the claims of the papal authority over other nations.

Roman churchman Cencio Sevelli succeeds him as Honorius III.

Later in this year, Honorius approves the formation of Dominic’s Friars Preachers, also known as the Order of Preachers (OP) or Dominicans.

King Andrew II of Hungary had married Yolanda, the niece of Henry I, the Emperor of Constantinople, in February 1215.

When the Emperor Henry I died on July 11, 1216, Andrew had planned to acquire the imperial throne, but the barons of the Latin Empire had proclaimed his father-in-law, Peter of Courtenay, their emperor.

Andrew has decided nonetheless to fulfill his father's oath and makes preparations for a Crusade to the Holy Land in 1217, one of several foreign misadventures that will prove costly to Hungary.

Pope Innocent III, having since 1208 planned a crusade in order to destroy the Ayyubid Empire and to recapture Jerusalem, had in April 1213 issued the papal bull Quia maior, calling all of Christendom to join a new crusade.

This had been followed in 1215 by another papal bull, the Ad Liberandam.

Innocent had in 1215 summoned the Fourth Lateran Council, where, along with the Latin Patriarch of Jerusalem, Raoul of Merencourt, he had discussed the recovery of the Holy Land, among other church business.

Pope Innocent wants it to be led by the papacy, as the First Crusade should have been, in order to avoid the mistakes of the Fourth Crusade, which had been taken over by the Venetians.

Innocent plans for the crusaders to meet in 1216 at Brindisi and to ensure that the crusaders will have ships and weapons prohibits trade with the Muslims.

Every crusader will receive an indulgence, including those who simply help pay the expenses of a crusader, but do not go on crusade themselves.

The message of the crusade had been preached in France by Robert of Courçon; however, unlike other Crusades, not many French knights have joined, as they are already fighting the Albigensian Crusade against the heretical Cathar sect in southern France.

Oliver of Cologne had preached the crusade in Germany, and King Frederick II of Sicily, a Hohenstaufen and grandson of Frederick I Barbarossa, twice crowned king of the Germans, had in 1215 attempted to join.

Frederick was the last monarch Innocent wanted to join the movement, as he had challenged the Papacy (and would do so in the years to come).

Innocent dies, however, in 1216.

Honorius III, who succeeds Innocent on July 28, immediately activates Innocent's plan to restore the kingdom of Jerusalem, organizing crusading armies led by King Andrew II of Hungary and duke Leopold VI of Austria.

Andrew and his troops, having embarked on August 23, 1217, in Spalato, had been transported by the Venetian fleet, the largest European fleet in the era.

They land on October 9 on Cyprus, whence they sail to Acre and join John of Brienne, ruler of the Kingdom of Jerusalem, Hugh I of Cyprus, and Prince Bohemond IV of Antioch to fight against the Ayyubids in Syria.

Jerusalem’s walls and fortifications are demolished to prevent the Christians from being able to defend the city, if they do manage reach it and take it.

Muslims flee the city, fearing a repeat of the bloodbath of the First Crusade in 1099.

The well-mounted army of Andrew II of Hungary on November 10 defeats Sultan Al-Adil I at Bethsaida on the Jordan River.

Muslim forces retreat in their fortresses and towns.

The catapults and trebuchets do not arrive in time, so Andrew’s assaults on the fortresses of the Lebanon and on Mount Tabor are fruitless.

Andrew afterwards spends his time collecting alleged relics.