After the Battle of Talas in 751, the Abbasid Caliphate and Tang China established a mutually beneficial trading relationship that greatly enriched both empires.

The Siege of Jerusalem, during the First Crusade, ended in victory for Crusaders and the forces of Christendom. It also ended in a violent massacre, as the entire Muslim and Jewish population of the city was mercilessly slaughtered.

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.