The First Crusade
The First Crusade was launched in 1095 by Pope Urban II with the primary goal of responding to the appeal from Byzantine Emperor Alexius I. The Emperor requested that western volunteers come to their aid and repel the Seljuk Turks in Anatolia, modern-day Turkey. The Crusade soon turned into a religious conquest and a secondary goal was created - reconquer the sacred city of Jerusalem and the Holy Land and free the Eastern Christians from Islamic rule. What started as an appeal quickly turned into a wholesale Western migration and conquest of territory outside of Europe. Both knights and peasants from many nations of Western Europe travelled over land and by sea towards Jerusalem and captured the city in July 1099, establishing the Kingdom of Jerusalem and other Crusader states.
The Second Crusade
The Second Crusade (1145-1149) was called by Pope Eugene III following the fall of the County of Edessa, the first Crusader State to be founded in the First Crusade and the first to fall. Because of lack of cooperation between the separate European and Byzantine armies, they were defeated separately by the Seljuk Turks, resulting in an astounding defeat to the Crusaders and the end of the Second Crusade.
The Third Crusade
The Third Crusade (1189-1192), also known as the Kings' Crusade, was a failure also. It started when the once-fighting but now unified Muslim empires under Saladin captured Jerusalem. Spurred by religious zeal, Henry II of England and Philip II of France ended their conflict with each other to lead a new Crusade (although Henry's death in 1189 put the English contingent under the command of Richard I instead). The elderly Holy Roman Emperor Frederick I Barbarossa responded to the call to arms, and led a massive army across Anatolia, but died from drowning before reaching the Holy Land. Many of his discouraged troops left to go home. After some military successes, the Christian powers argued over the spoils of war; frustrated with Richard, Frederick's successor Leopold V of Austria and Philip left the Holy Land in August 1191. On September 2, 1192, Richard and Saladin finalized a treaty by which Jerusalem would remain under Muslim control, but which also allowed unarmed Christian pilgrims to visit the city. Richard departed the Holy Land on October 9. The failure of the Third Crusade would lead to the call for a Fourth Crusade six years later.
The Fourth Crusade
The Road to War
After the failure of the Third Crusade (1189–1192), there was little interest in Europe for another crusade against the Muslims. Jerusalem had now become controlled by the Ayyubid dynasty, which ruled all of Syria and Egypt, except for the few cities along the coast still controlled by the crusader Kingdom of Jerusalem, now centered on Acre. The Third Crusade had also established a kingdom on Cyprus.
Pope Innocent III succeeded to the papacy in 1198, and the preaching of a new crusade became the goal of his pontificate. His call was largely ignored by the European monarchs: the Germans were struggling against Papal power, and England and France were still engaged in warfare against each other. However, due to the preaching of Fulk of Neuilly, a crusading army was finally organized at a tournament held at Écry by Count Thibaut of Champagne in 1199. Thibaut was elected leader, but he died in 1200 and was replaced by an Italian count, Boniface of Montferrat. Boniface and the other leaders sent envoys to Venice, Genoa, and other city-states to negotiate a contract for transport to Egypt, the object of their crusade; one of the envoys was the future historian Geoffrey of Villehardouin. Genoa was uninterested, but in March 1201 negotiations were opened with Venice, which agreed to transport 50,000 crusaders, a very ambitious number. This agreement required a full year of preparation on the part of the Venetians to build numerous ships and train the sailors who would man them, all the while curtailing the city's commercial activities. The crusading army was expected to comprise 5,000 knights (as well as 5,000 horses), 10,000 squires (and horses), and 35,000 foot-soldiers.
The crusading army that set out from Venice in October 1202 originated from areas within France. It included men from Blois, Champagne, Amiens, Saint-Pol, the Ile-de-France and Burgundy. Several other regions of Europe sent substantial contingents as well, such as Flanders and Montferrat. Other notable groups came from the Holy Roman Empire, including the men under Bishop Martin of Pairis and Bishop Conrad of Halberstadt, together in alliance with the Venetian soldiers and sailors led by the doge Enrico Dandolo. The crusade was to make directly for the centre of the Muslim world, Cairo, ready to sail on June 24, 1202. This agreement was ratified by Pope Innocent, with a solemn ban on attacks on Christian states.
The Egyptian Campaign
The army set sail from Venice on June 25, 1202 after the extensive preparations, and after an uneventful voyage arrived at North Africa on December 8, 1202. They encountered no initial resistance and advanced toward Alexandria despite the goal of the Crusade. They were arrayed before the city by December 16 and, after a short siege, captured it with minimal losses on December 20. The Siege of Alexandria had been won.
After capturing Alexandria and leaving a small occupying force, the army marched on Cairo. When they had almost gotten there, they encountered a large Muslim army sent out to stop them by overconfident leaders. So on January 5, 1203 they went to battle, the Battle of the Lower Nile. The outnumbered crusaders seemed to be doomed from the start on paper, but they had the advantage of knights and superior weaponry, so after a long and bloody battle the Muslims were routed with terrible losses. At the end of the day the field of battle was littered with the bodies of Muslim infidels with a crusader body here and there.
After winning their battle the now high-spirited crusaders marched on Cairo, arriving there the next day and setting up siege engines. Thus began the Siege of Cairo. The siege was more costly for the crusaders than the Siege of Alexandria, but was somewhat short nonetheless, ending on January 24, 1203 with the capture of the Muslim citadel. Muslim Egypt had been captured.
The Middle East Campaign
Despite the seemingly unstoppable might of the Muslim armies, Egypt had been captured. And they weren't as unified as they seemed, with much fighting going on between the kingdoms of the sons of Saladin, weakening the empires militarily, financially, and politically. So when the crusaders who had captured Egypt marched out to the Sinai peninsula and towards the remnants of the Kingdom of Jerusalem, the Byzantine Emperor, with a force of 42,000, marched out to form an unexpected pincer against the Ayyubids, capturing much of western Turkey.
The crusader armies swept quickly into the Kingdom of Jerusalem, virtually unopposed, and combined their army with that of the Kingdom, adding 1,500 knights and their horses, in addition to 3,000 squires and 12,000 foot-soldiers. From there they rushed into the lands of the Abbasids, driving toward Baghdad, with a force being dispatched to take Damascus.
In the following weeks the Abbasid armies were shattered, Damascus was captured with the help of the Byzantines, for they had fought their way to Damascus through an army that was going to hit the besiegers from behind, ending the siege. But the army was destroyed in the Battle of Damascus and the city captured on February 27, 1203 after the Siege of Damascus.
Meanwhile, the main crusader army encountered the mustered Abbasid army on the banks of the Euphrates River on February 12, 1203 and won the costly Battle of the Euphrates. The crusaders, despite their losses, drove on toward Baghdad, arriving and beginning the Siege of Baghdad on February 17, 1203. The siege dragged on, assault after assault being driven back, but the walls slowly started to crack and crumble. Relief finally came in the form of the small crusader force and 25,000 Byzantines. With this sudden reinforcement and doubling of siege engines the walls were breached and the combined armies rushed through, fighting in the streets and finally taking the citadel on April 19, 1203, thus ending the siege.
Though the Muslim empires seemed to have much more land left, they were rebellious and fractured; many provinces defected and joined the Crusaders and the empires were defeated in short order. The Muslims, overall, had lost 376,043 men in the war, compared the the Crusaders' 21,469 men and the Byzantines' 17,897.