The Islamic civil war was fought in the mid-seventh century between the Sunni forces of the Umayyad Caliphate and the Shiite forces loyal to Mohammed’s descendant Ali. The civil war ended in victory for the Sunni and the formation of the Umayyad Caliphate as the ruler of the Islamic world. Ali was killed in the war, but the Shiite continued to follow his descendants and remained outside of the Sunni community.

The Battle of Ain Jalut was fought in 1260 between the Mongols and the Mamluk dynasty of North Africa and the Middle East. The battle ended in victory for the Mamluks and halted the Mongol expansion into the Middle East.

The Islamic civil war of the mid-seventh century led to a permanent split between the Sunni majority and the Shiite minority in the Islamic world. The Sunni majority were united under the authority of the Umayyad Caliph, whereas the Shiite minority followed Ali and his descendants.

The Song Dynasty was conquered by the Mongols during the second-half of the thirteenth century. The Mongols, led by Kublai Khan, established the Yuan Dynasty in China.

The Hundred Years' War was fought between the Kingdom of France and the Kingdom of England from 1337 until 1453. It is one of the most important and notable conflicts of the Middle Ages and as a result of the conflict strong national identities were formed in each nation and the subsequent theory and idea of 'nationalism' was founded. 

In medieval Europe, the Pope had the authority to declare a crusade. A crusade was a holy war that was meant to advance the cause of Christianity and strengthen the power of the Catholic church. The most famous crusades are those launched against the Muslim kingdoms of the Middle East that were generally intended to recapture Jerusalem and the Holy Land.

Enrico Dandolo ruled over the Italian city-state of Venice at the height of its power and influence. Venice, at the time, was an influential maritime city-state and was immensely wealthy as a result of trade in the Mediterranean. Enrico Dandolo is most notable for calling for the Fourth Crusade.

Beginning in the tenth century, the Abbasid Caliphate experienced a steady decline in power. Throughout the tenth century, they lost territory due to nomadic invaders and the chaos caused by Sunni-Shiite divisions. In the eleventh century, the Abbasid capital, Baghdad, was captured by the Seljuk Turks. Although the Seljuk Turks allowed the caliph to continue ruling in a limited capacity, the Abbasid Caliphate would never again rule with any real authority.

All of these were part of the longterm consequences of the Crusades. The role of knights in the Crusades led to the growth of chivalry as a social code in Europe. Relations between the Islamic and Christian world naturally worsened as a result of two centuries of warfare and massacres. In many ways, we are still feeling the effects of this today; however, there were positive consequences too. The reawakening of classical knowledge, that had for so long been preserved by the Byzantines and the Islamic empires of the Middle East, led to the Renaissance in Europe. The exposure to Middle Eastern technology led to greater technological exchange in Eurasia, which was particularly beneficial to the Europeans.

In the late-eleventh century, at the time of the First Crusade, the Islamic world was highly fragmented and resistance was weak and poorly organized. The Abbasid Caliphate was very weak at this time and incapable of coordinating resistance. However, over time the Islamic resistance grew much stronger and by the time of the Third Crusade (1189 - 1212), they were able to hold off the Christian advance on Jerusalem.