These times were also very turbulent for the Russians, the newest nation in the Orthodox family, when the Mongols destroyed Kiev in 1240, and Russia became part of Genghis Khan's Mongol Empire. The Eastern Romans' tradition survived these tragedies and the Church showed astonishing internal strength and flexibility. Until the Crusades, and in spite of the exchanges of anathemas between the Patriarch of Constantinople Michael Cerularius and the papal legates in 1054, Orthodox Christians did not view the break with the West as a final schism. The people viewed the break of communion with the West as temporary, due to the take-over of the patriarchate of Rome by harsh and uneducated Germanic barbarians, and that ultimately the former unity of the Christian world under the one legitimate Roman Emperor of Constantinople, and the five patriarchates would be restored. This opinion proved to be too utopian as these crusaders started their "holy mission" by replacing the Orthodox patriarchs of Antioch and Jerusalem with Latin ones (1098-99), instead of trying to reestablish Christian unity in the struggle against Islam.

The Crusaders: The Crusades began in 1095 with Pope Urban II calling for a great Christian campaign to free Jerusalem from the Muslim Seljuks, and ended in the late 13th century. The pope was also tempted by a call for help from the Eastern Roman Emperor Alexius I. The first and greatest Crusade was successful in occupying Jerusalem and establishing a Western Christian military presence in the Near East that lasted for two centuries. Arabs called the Western Crusaders "Franks," while only the Eastern Romans were known to the Arabs as "Romans" (as they are called in Qur'anic texts also). The early Crusaders were unorganized masses with various conflicting factions and leaders, who had no agreement with the Eastern Roman Emperor or any sympathy for Orthodoxy.

The Journey to the East: the Crusaders followed different routes to Constantinople, where they would all meet. As they marched east, they were joined by thousands of nobles, knights and peasants. Some were motivated by a true zeal, others longed for the riches of the East. They knew little about the Eastern Roman Empire or Orthodox Christianity, and many had no sympathy for Eastern Orthodox Christianity, which did not recognize the pope's legitimacy or the controversial new doctrines that Rome had gradually added after the seventh century, used the Greek language rather than Latin, and most important of all, exchanged excommunications with Rome 40 years earlier. The Crusaders knew even less about Islam or Muslim life, and the papal promises of a better salvation became an excuse for many to unleash savage attacks in the name of Christianity on Muslims and Orthodox Christians in major cities.

Antioch: Bohemond of Taranto took Antioch in June 1098, before moving on to Jerusalem. The siege of Jerusalem resulted in a bloody and destructive victory in July 1099, in which many of the inhabitants were massacred. As a result, the Crusaders formed the Latin Kingdom of Jerusalem under Godfrey of Bouillon, who was succeeded by his brother Baldwin. In addition to the Latin Kingdom in Jerusalem, three other Crusader states were founded: the County of Tripoli, in modern Lebanon; the Principality of Antioch, in modern Syria; and the County of Edessa, in modern northern Syria and southern Turkey. (See Map)

Orthodox patriarchs, John of Antioch and Simon of Jerusalem, were forced to leave their seats and died in exile. Patriarchs of Antioch had to reside in Cyprus, Damascus, or Constantinople until the end of the crusades.

The Crusades in the 12th Century: In 1144, the Muslims recaptured the city Edessa in northeastern Syria on the Euphrates River. Edessa was strategically important because it protected the territories near the Syrian coast. This led Pope Eugenius III to launch the Second Crusade. The campaign included Germany's "Holy Roman Emperor" Conrad III and France's King Louis VII. Only a portion of that force succeeded in reaching Jerusalem in 1148. King Baldwin III of Jerusalem persuaded the Crusaders to attack Damascus in July. The attack failed to take the city and the French king returned to France after losing most of his army.

Military Religious Orders: To strengthen the idea of knighthood, chivalry, and "holy war", an idea rejected by the Orthodox Church, a few military religious orders were established In the 1120s and 1130s. Men who joined these orders took vows of chastity and obedience similar to those taken in monasteries, but were also soldiers dedicated to war in the East. The most famous of these orders were the Knights of St John of Jerusalem (Hospitalers), the Poor Knights of Christ, and the Knights of the Temple of Solomon (Templars).

The Third Crusade: In 1187 Saladin the Ayyubid defeated a large army at Hitteen and took Jerusalem. In response, the Western Church called for a new Crusade. Three Western rulers participated this time: Richard I of England (the Lion-Hearted), Philip II of France, and Frederick I Barbarossa of Germany. On the way to the Holy Land, Frederick Barbarossa died and most of his armies retreated to Germany, Philip II returned two years later in 1191, and Richard was unable to recapture Jerusalem from Saladin, but nevertheless succeeded in taking control of the Mediterranean coast. In October 1192 Richard left Palestine after securing the remains of the Latin Kingdom, which would last for another century.

The Sacking of Constantinople: In 1199, Pope Innocent III called for another Crusade to recapture Jerusalem. However, the Crusaders were unable to pay the ruler of Venice, who was supposed to transport them by sea to Palestine. After bargaining with the Venetians, they agreed to attack the city of Zara, a trading port on the Adriatic Sea in Hungary, and a rival of Venice. When Innocent III learned of the expedition he excommunicated it's members, but the Crusade continued to Zara in 1202. The Venetians then convinced the Crusaders to attack the Eastern Roman capital of Constantinople, which fell on April 13, 1204. For three days the Crusaders sacked the city, after which they proclaimed the Latin Empire of Constantinople.

After forcing the city's legitimate patriarch to exile, The Venetian Latin hierarch Thomas Morosini was installed as patriarch of Constantinople and was surprisingly confirmed as such by Pope Innocent III. At that point the Orthodox became aware of the full seriousness of the new papal claims over the whole church. The Orthodox patriarch John Camaterus fled to Bulgaria and died there in 1206. His successor, Michael Autorianus, was elected in Nicaea (1208), and was recognized as the legitimate patriarch by the entire Orthodox world. The Eastern Orthodox resistance sprang up in Epirus, Trebizond, and Nicaea. In addition, several new Crusader states sprang up in the Balkans, and along the coast of the Black Sea. The Crusaders of this campaign never fought the Muslims, but applied their hostility towards the politically declining Christians in the East.

More Crusades: Crusades after the Fourth were also military enterprises led by rulers motivated by personal greed. Holy Roman Emperor Frederick II prepared to lead a Crusade in 1215, but his crusade was not launched until 1227. Pope Gregory IX encouraged the crusade, which sailed from Italy in August 1227. After a few days Frederick falls ill and his forces return. The pope receives this news with great outrage and excommunicates the Emperor. In June 1228, Frederick leaves to Palestine. After reaching the Holy Lands Frederick proved to be a man of peace, wisdom, and a powerful personality. He carried out most of his Crusade by means of diplomatic negotiations with the Egyptian Sultan Al-Kamil of Egypt, which produced a treaty by which the Arabs restored Jerusalem to the Crusaders and guaranteed ten years of peace. However, Frederick was forced to return after the Pope had invaded his territories in Sicily.

On June 5, 1249 Louis IX, King of France, landed in Egypt and captured Damietta. A later attack on Cairo in the spring of 1250 proved to be a catastrophe, which resulted in Louis' surrender in April 1250. After paying a huge ransom, Louis sailed to Palestine and spent four years strengthening and fortifying the Latin Kingdom. In 1270, King Louis launched a campaign against the city of Tunis rather than Egypt. This crusade ended with his death in the summer of 1270.

The Last of The Crusaders: The year 1260 witnessed the rise of Sultan Baybars the Mamluk in Egypt (Mamluks were slaves bought by Muslim kings to fight in their armies). After achieving victory over the Mongols, the Ayyubids, the Assassins, and his own Sultan Al-Muzaffar Sayf Al Din Qutuz, he launched frequent raids against the Crusaders between 1265 and 1271. In 1265 he captured Arsuf from the Hospitalers. In 1266 he occupied 'Atlit, Haifa, and forced the surrender of the Knights Templar garrison in Safed after a heavy siege. Two years later, Jaffa surrendered without resistance.

The most important city taken by Baybars was Antioch in May 1268; his army destroyed the city, and the patriarchal seat of Antioch was moved to Damascus permanently later in 1386 with the patriarch Pachomius.

By 1271 he seized most of the Crusaders' citadels, and they never recovered from these losses. He also attacked the Christian Armenians, who were allies of the Mongols, and destroyed their major cities. In 1276, he defeated the Seljuks and their Mongol allies, and reached Caesarea in Cappadocia. Baybars had good diplomatic relations with Emperor Michael VIII Palaeologus, who restored the old mosque in Constantinople and permitted the Egyptian merchants to sail through the Hellespont and Bosporus.

The Last Eastern Roman Dynasty: Emperor Michael VIII Palaeologus recaptured Constantinople from the Latins in 1261 and founded the Palaeologan dynasty, which ruled the Empire until 1453. The Palaeologan Empire was limited in terms of finances, land, and central authority. Agricultural conditions worsened, and Turkish raids devastated the land. The Ottoman Turks conquered the remains of the Eastern Roman Asia Minor early in the 14th century. In 1354 they overran the Balkans and finally sacked Constantinople in 1453. They succeeded in claiming the Caliphate, and Muslim kingdoms in Syria and Egypt quickly fell in their hands.