The Black Death devastated populations in parts of the world connected by trade in the fourteenth century-Africa, Asia, and Europe. Italy and China were particularly hard hit. The Black Death, however, helped end serfdom in parts of Europe (although not in Russia) and inspired works of literature, like Boccaccio's Decameron (1353). 

The Portuguese capture of Ceuta (a port city in Morocco) in 1415 began the age of exploration as the Portuguese from this point began overseas exploration to the south and west, and were the first Europeans since the Vikings to do this. The Crusades occurred long before this, and simply led to increased European contact and interest in overseas lands, which eventually led to the age of exploration. Columbus' "discovery" of the Americas and the Portuguese reaching and circumnavigating southern Africa all occurred decades after the capture of Ceuta, once the age of exploration was well underway.

The Black Death of the mid 14th century killed so many Europeans that it caused a labor shortage, allowing peasants and urban workers to demand greater economic rights and freedoms in exchange for their labors, leading to the end of serfdom in western Europe and the erosion of medieval feudalism. The collapse of the Roman empire and the invasions of Europe by the Arabs, Vikings, and Magyars were all events that occurred centuries before the Black Death. Europeans would not develop the germ theory of disease until the 19th century, centuries after the Black Death.

The Ottoman Sultan Mehmed II led an army to Constantinople in the spring of 1453 to siege the city. After a month, the Ottomans were successful in sacking the city, and destroying the Eastern Romany (or Byzantine) Empire. The effect of this sack was massive, allowing the Ottoman armies free reign into Europe, giving the Ottomans control of the Bosphorus Strait and the Black Sea, sending Greek scholars into exile,  and generally worsening relations between Christian Europe and Islamic governments in the Middle East.

The Battle of Talas was fought between the Arab Abbasid Caliphate and the Chinese Tang Dynasty in 751 CE. Prior to the battle, Chinese forces had been spreading rapidly westward and facing little opposition; however, at the Battle of Talas, they were defeated by the Arab forces, and Chinese expansion was halted for several centuries. The battle is considered important for transferring control over the “Silk Road” from Chinese to Arab hands and for turning back the massive forces of the Tang Dynasty. Also, it is sometimes said that Arabs learned the art of paper making from the Chinese prisoners they captured in the battle, thus spreading paper-making technology to the Middle East and eventually Europe.

Mehmet II was a Sultan of the Ottoman Empire who in 1453 conquered the city of Constantinople, later renamed Istanbul. Mehmet II is remembered as a great hero in Turkish society and is often referred to as Mehmet the Great or Mehmet the Conqueror.

After the death of the prophet Muhammad, the forces of Islam expanded dramatically across North Africa and the Middle East. By 732 CE, they had crossed into mainland Europe and controlled much of modern-day Spain and southern France. At the Battle of Tours, they were defeated by the Frankish forces led by Charles Martel (often called Charles the Hammer). This is often considered a turning point in world history as the forces of Islam would never again penetrate so far into Europe. 

The First Crusade was initiated by Pope Urban II in 1095 with the original aim of assisting the Byzantine Empire in defending itself against the invading Turkish forces; however, the mission quickly expanded to include liberating the Holy City of Jerusalem from under Muslim control. Jerusalem was “liberated” in 1099, but this incident would mark several hundred years of competition between the Christian forces of Europe and the Islamic forces of the Near East that are collectively called “the Crusades.”

The First Crusades were initiated by Pope Urban II in 1095 with the primary goal of retaking the Holy Land and Jerusalem from the "infidels." 

The armies of the First Crusade was made up primarily of young French soldiers and nobles.