The period of Islamic Arab territorial expansion had been over since the 8th century. Syria and Palestine's remoteness from the focus of Islamic power struggles enabled relative peace and prosperity.

Byzantine emperor Basil II extended the empire's territorial recovery to its furthest extent in 1025, with frontiers stretching east to Iran. It controlled Bulgaria, much of southern Italy, and suppressed piracy in the Mediterranean Sea.

Byzantium's attempted confrontation in 1071 to suppress the Seljuks' sporadic raiding led to the defeat at the Battle of Manzikert.

Jerusalem was taken from the Fatimids by the Turkish warlord Atsiz, who seized most of Syria and Palestine as part of the expansion of the Seljuks throughout the Middle East. The Seljuk hold on the city resulting in pilgrims reported difficulties and the oppression of Christians.

Pope Urban II hosted the Council of Clermont in November 1095 that resulted in the mobilization of Western Europe to go to the Holy Land.

Immediately after Urban's proclamation, the French priest Peter the Hermit led thousands of mostly poor Christians out of Europe in what became known as the People's Crusade. In transit through Germany, these Crusaders spawned German bands who massacred Jewish communities in what became known as the Rhineland massacres.

They were destroyed in 1096 when the main body of Crusaders was annihilated at the battle of Civetot.

Alexios I Komnenos persuaded many of the princes to pledge allegiance to him. He also convinced them their first objective should be Nicaea. Buoyed by their success at Civetot, the over-confident Seljuks left the city unprotected, thus enabling its capture after the siege of Nicaea in May–June 1097.

The first experience of Turkish tactics occurred when a force led by Bohemond and Robert was ambushed at the Battle of Dorylaeum in July 1097. The Normans resisted for hours before the arrival of the main army caused a Turkish withdrawal.

The Crusader army marched to the former Byzantine city of Antioch that had been in Muslim control since 1084. The Crusaders began the siege of Antioch in October 1097 tell Antioch was captured.

Bohemond remained in Antioch, retaining the city, despite his pledge to return it to Byzantine control, while "Raymond IV, Count of Toulouse" led the remaining Crusader army rapidly south along the coast to Jerusalem. An initial attack on the city failed, and the siege of Jerusalem of 1099 became a stalemate until they breached the walls on 15 July 1099. For two days the Crusaders massacred the inhabitants and pillaged the city.

Godfrey of Bouillon further secures the Frankish position by defeating an Egyptian relief force at the Battle of Ascalon in August 1099.

The First Crusade led to the establishment of the Kingdom of Jerusalem under Godfrey of Bouillon.

The first of the Crusader states––Edessa––was also the first to fall after the first siege of Edessa, arriving on 28 November 1144. Calls for a Second Crusade were immediate and were the first led by European kings. The disastrous performance of this campaign in the Holy Land damaged the standing of the papacy, soured relations between the Christians of the kingdom and the West for many years, and encouraged the Muslims of Syria to even greater efforts to defeat the Franks. The dismal failures of this Crusade then set the stage for the fall of Jerusalem, leading to the Third Crusade. Concurrent campaigns as part of the Reconquista and Northern Crusades are also sometimes associated with this Crusade.

Eugene III recently elected pope, issued the bull Quantum praedecessores on 1 December 1145, the first such papal bull issued calling for a new crusade, meant to be more organized and centrally controlled than the First. The armies would be led by the strongest kings of Europe and a route would be pre-planned. The French contingent departed in June 1147.

The French contingent departed in June 1147.

In the spring of 1147, Eugene III authorized the expansion of his mission into the Iberian peninsula, equating these campaigns against the Moors with the rest of the Second Crusade. The successful siege of Lisbon was acquired from 1 July to 25 October 1147.

In the north, some Germans were reluctant to fight in the Holy Land while the pagan Wends were a more immediate problem. The resulting Wendish Crusade of 1147 was partially successful but failed to convert the pagans to Christianity.

A few days later, they were again victorious at the battle of the Meander, late in 1147.

The French met the remnants of Conrad's army in northern Turkey, and Conrad "Conrad III of Germany" joined Louis' "Louis VII of France" force. They fended off a Seljuk attack at the battle of Ephesus on 24 December 1147.

Louis (Louis VII of France) was not as lucky at the battle of Mount Cadmus on 6 January 1148, where the Seljuk army inflicted heavy losses on the Crusaders. The army sailed for Antioch in January, almost totally destroyed by battle and sickness.

The Crusader army arrived at Antioch on 19 March 1148 with the intent of moving to retake Edessa, but the objective was changed to Damascus.

Bad luck and poor tactics led to the disastrous five-day siege of Damascus from 24 to 28 July 1148.

Six-month siege of Tortosa, ending on 30 December 1148 with a defeat for the Moors.

The news of the disastrous defeat at the Battle of Hattin and the subsequent fall of Jerusalem gradually reached Western Europe.

The siege of Jerusalem lasted from September 20 to October 2, 1187, when Balian of Ibelin surrendered the city to Saladin.

Urban III died shortly after hearing the news, and his successor Gregory VIII issued the bull Audita tremendi on 29 October 1187 describing the events in the East and urging all Christians to take up arms and go to the aid of those in the Kingdom of Jerusalem, calling for a new crusade to the Holy Land––the Third Crusade––to be led by Frederick Barbarossa and Richard I of England.

Frederick sent an ultimatum to Saladin, demanding the return of Palestine and challenging him to battle and in May 1189, Frederick's host departed for Byzantium.

Richard I and Philip II of France agreed to go on the Crusade in January 1188. Arriving in the Holy Land, Richard had led his support to the stalemated siege of Acre. The Muslim defenders surrendered on 12 July 1191.

In March 1190, Frederick embarked to Asia Minor. The armies coming from western Europe pushed on through Anatolia, defeating the Turks and reaching as far as Cilician Armenia.

On 10 June 1190, Frederick drowned near Silifke Castle. His death caused several thousand German soldiers to leave the force and return home. The remaining German army moved under the command of the English and French forces that arrived shortly thereafter.

On 20 August 1191, Richard had more than 2,000 prisoners beheaded at the so-called massacre of Ayyadieh. Saladin subsequently ordered the execution of his Christian prisoners in retaliation.

Richard remained in sole command of the Crusader force after the departure of Philip II on 31 July 1191.

Richard moved south, defeating Saladin's forces at the Battle of Arsuf on 7 September 1191.

On 12 December 1191 Saladin disbanded the greater part of his army. Learning this, Richard pushed his army forward, to within 12 miles from Jerusalem before retreating back to the coast. The Crusaders made another advance on Jerusalem, coming within sight of the city in June before being forced to retreat again. Hugh III of Burgundy, leader of the Franks, was adamant that a direct attack on Jerusalem should be made. This split the Crusader army into two factions, and neither was strong enough to achieve its objective. Without a united command the army had little choice but to retreat back to the coast.

On 27 July 1192, Saladin's army began the battle of Jaffa, capturing the city. Richard's forces stormed Jaffa from the sea and the Muslims were driven from the city. Attempts to retake Jaffa failed and Saladin was forced to retreat.

On 2 September 1192 Richard and Saladin entered into the Treaty of Jaffa, providing that Jerusalem would remain under Muslim control while allowing unarmed Christian pilgrims and traders to freely visit the city. This treaty ended the Third Crusade.

Henry VI launched the Crusade of 1197. While his forces were en route to the Holy Land, Henry VI died in Messina on 28 September 1197. The nobles that remained captured the Levant coast between Tyre and Tripoli before returning to Germany. The Crusade ended on 1 July 1198 after capturing Sidon and Beirut.

In 1198, the recently elected Pope Innocent III announced a new crusade, organized by three Frenchmen: Theobald of Champagne; Louis of Blois; and Baldwin of Flanders. After Theobald's premature death, the Italian Boniface of Montferrat replaced him as the new commander of the campaign.

When the crusade entered Constantinople, Alexios III fled and was replaced by his nephew. The Greek resistance prompted Alexios IV to seek continued support from the crusade until he could fulfill his commitments. This ended with his murder in a violent anti-Latin revolt. The crusaders were without ships, supplies, or food, leaving them with little option other than to take by force what Alexios had promised. The Sack of Constantinople involved three days of pillaging churches and killing much of the Greek Orthodox Christian populace. At the conclusion of the sack of Constantinople, most Crusaders viewed the continuation of their mission as an impossibility. In the end, the crusade accomplished nothing toward its goal of liberating Jerusalem.

Innocent III called for another Crusade at the Fourth Lateran Council. In the papal bull Quia maior he codified existing practice in preaching, recruitment, and financing the Crusades. A force—primarily raised from Hungary, Germany, Flanders—led by King Andrew II of Hungary and Leopold VI, Duke of Austria achieved little in what is categorized as the Fifth Crusade. The strategy was to attack Egypt because it was isolated from the other Islamic power centers, it would be easier to defend, and was self-sufficient in food.

Leopold VI and John of Brienne besieged and captured Damietta, but an army advancing into Egypt was compelled to surrender. Damietta was returned, and an eight-year truce agreed.

Holy Roman Emperor Frederick II was excommunicated for frequently breaking an obligation to the pope to join the crusade. In 1227 he embarked on a crusade but was forced to abandon it due to illness but in 1228 he finally reached Acre. Culturally, Frederick was the Christian monarch most empathetic to the Muslim world, having grown up in Sicily, with a Muslim bodyguard. Despite his ex-communication by Pope Gregory IX, his diplomatic skills meant the Sixth Crusade was largely a negotiation supported by force.

Politics in the 13th-century eastern Mediterranean were complex, with numerous powerful and interested parties. The French were led by the very devout Louis IX of France and his ambitiously expansionist brother Charles I of Naples. Communication with the Mongols was hindered by the enormous distances involved. Louis sent an embassy to the Mongols in Iran in 1249 seeking a Franco-Mongol alliance.

Louis organized a new crusade, called the Seventh Crusade, to attack Egypt, arriving in 1249.

Louis IX of France was captured as he retreated to Damietta.

Louis IX of France was defeated at Mansura.

Louis IX of France remained in Syria until 1254 to consolidate the Crusader states.

The threat presented by an invasion by the Mongols led to Qutuz seizing the sultanate in 1259 and uniting with another faction led by Baibars to defeat the Mongols at Ain Jalut. The Mamluks then quickly gained control of Damascus and Aleppo before Qutuz was assassinated, most probably by Baibers.

Between 1265 and 1271, Sultan Baibars drove the Franks to a few small coastal outposts. Baibars had three key objectives: to prevent an alliance between the Latins and the Mongols, to cause dissension among the Mongols (particularly between the Golden Horde and the Persian Ilkhanate), and to maintain access to a supply of slave recruits from the Russian steppes. He supported King Manfred of Sicily's failed resistance to the attack of Charles and the papacy. Dissension in the crusader states led to conflicts such as the War of Saint Sabas. Venice drove the Genoese from Acre to Tyre where they continued to trade with Baibars' Egypt. Indeed, Baibars negotiated free passage for the Genoese with Michael VIII Palaiologos, Emperor of Nicaea, the newly restored ruler of Constantinople.

In 1270 Charles turned his brother King Louis IX's crusade, known as the Eighth, to his own advantage by persuading him to attack his rebel Arab vassals in Tunis. The crusader army was devastated by disease, and Louis himself died in Tunis on 25 August. The fleet returned to France.

Lord Edward, the future king of England, and a small retinue arrived too late for the conflict but continued to the Holy Land in what is known as the Ninth Crusade. Edward survived an assassination attempt, negotiated a ten-year truce, and then returned to manage his affairs in England. This ended the last significant crusading effort in the eastern Mediterranean.

The Fall of Tripoli was the capture and destruction of the Crusader state, the County of Tripoli (in what is modern-day Lebanon), by the Muslim Mamluks.

The mainland Crusader states were finally extinguished with the siege of Acre in 1291. It is reported that many Latin Christians evacuated to Cyprus by boat, were killed or enslaved.