In the 50 years following the First Crusade, the Latin states in the East were consolidated, but there were also growing tensions and new challenges. Against this backdrop, the fall of the County of Edessa in December 1144 at the hands of Zengi, the atabeg of Aleppo and Mosul, was a catastrophic event. Founded in 1098 by the future King Baldwin of Boulogne, Edessa was the first Crusader state, as well as the northernmost, weakest, and least populated. It was constantly exposed to Muslim attacks, and news of its fall reached Europe at the beginning of 1145, and the fall was the catalyst for the Second Crusade. Furthermore, the Crusader States were also concerned about their relationship with the Byzantine Empire, as relations with the Byzantines were often tense. Indeed, efforts to strengthen and then retake parts of the collapsing Crusader States would fuel subsequent Crusades, and the Fourth Crusade notoriously ended with the Crusaders sacking Constantinople instead of proceeding to Jerusalem.

Naturally, the Fifth Crusade was launched as a result of the Fourth Crusade’s failure to retake Jerusalem, and Pope Innocent III’s goal of reclaiming Jerusalem, which had been lost in 1187, remained unchanged. At the same time, there was a truce between the Kingdom of Jerusalem and the Ayyubid Sultan al-‘Adil I, which was due to expire in 1217. The timing seemed favorable for a new initiative, particularly given the strengthening of Christendom in other regions such as Spain, where the victory at Las Navas de Tolosa in 1212 had secured much of the Iberian Peninsula against the Moors. The turning point for the proclamation of the Fifth Crusade was the Fourth Lateran Council in 1215, where Innocent III established a model for future Crusades, providing the enterprise with consistent legal, liturgical, and fiscal provisions.