In an attempt to correct this, the Caliphs invited Turkic warriors to restore them, but this did not work and led instead to the creation of a new power, the Great Seljuk Turk Empire, which stretched from Central Asia to Turkey. The Seljuks under Sultan Alp Arslan began entering Byzantine territory, which lead to a response under the Emperor Romanos IV Diogenes. The two armies met in eastern Anatolia in 1071. Half the Byzantine army didn’t even fight due to internal Byzantine politics leading to treachery. The Byzantine Emperor was captured and though released, the Empire fell into civil war.

Battles can make or break states and change the destiny of nations forever. As such, they represent some of humanity’s most important events. While there have been dozens of important, interesting battles over the past five thousand years of recorded warfare, here are five that changed history forever, though by no means is this list exhaustive. Instead, I have selected a wide range of battles from across different regions and times and have specifically avoided focusing on more well-known modern battles, many of which will be covered by The National Interest soon to mark the end of the Napoleonic Wars and World War II.

Milvian Bridge (313)

This seemingly random skirmish should have been just another battle in a series of long-forgotten skirmishes in the civil wars that consumed the Roman Empire during much of the third century. However, the fact that Constantine the Great won the battle to become the Roman Emperor was a major event in world history.

Constantine, who was fighting to become emperor, arrived near Rome to fight an army twice the size of his. The night before the battle, he allegedly saw a cross or chi-rho sign in the sky with the words “by this sign, you shall conquer.” He ordered his soldiers to paint the cross onto their shields and won the subsequent battle, becoming emperor in the process. He then began to patronize Christianity, leading to its spread from a small persecuted sect to the official religion of the empire by 380. His actions led to the establishment of an organized sort of Christianity that would play an important role in the Western world’s subsequent development. It is also inconceivable that Islam would take root and become so widespread had Christianity not first changed the religious orientation of much of the world away from polytheism toward monotheism.

Manzikert (1071)

Though not as well known as the later fall of Constantinople in 1453, the Battle of Manzikert was the what led to the inevitable crash of the Byzantine Empire, the Crusades, and the rise of Turkish power in Anatolia (the peninsula that makes up most of Turkey today).

The base of Byzantine power was Anatolia, rather than Greece itself. Just compare the population of Greece today (around 11 million) to Turkey (around 75 million). Anatolia was the base of Byzantine power in asserting control over the Balkans and parts of Italy and the Middle East. The Caliphs of Baghdad had ceased to hold effective power by 900 and a number of independent Islamic states arose on the Byzantine frontier, while the Caliphs themselves became puppets of temporal rulers.

In an attempt to correct this, the Caliphs invited Turkic warriors to restore them, but this did not work and led instead to the creation of a new power, the Great Seljuk Turk Empire, which stretched from Central Asia to Turkey. The Seljuks under Sultan Alp Arslan began entering Byzantine territory, which lead to a response under the Emperor Romanos IV Diogenes. The two armies met in eastern Anatolia in 1071. Half the Byzantine army didn’t even fight due to internal Byzantine politics leading to treachery. The Byzantine Emperor was captured and though released, the Empire fell into civil war.

Within a decade, the empire lost most of its heartland and had to call for help from the Pope, which lead to the Crusades. In the meantime, the Seljuks also captured Jerusalem from the Shia Fatimid Egyptian dynasty in 1073, making conditions worse for everyone there.

Second Battle of Tarain (1192)

The relatively obscure Second Battle of Tarain was ultimately the most important battle in the Indian subcontinent’s history because it made it what it is today. In geopolitical terms, the battle led to South Asia becoming politically a part of the greater Islamic world to its west.

Until the 12th century, most of India, one of the world’s wealthiest regions, was ruled by native Hindu and Buddhist kingdoms, though Islamic states had made some inroads into northwest India (parts of today’s Pakistan). However, in the late 12th century, one Muhammad of Ghor, a local ruler in today’s Afghanistan decided to do more than just raid India for loot—he wanted to establish a permanent Islamic empire in the subcontinent.

After conquering much of what is today Pakistan, he came face to face with a large Rajput (a Hindu warrior caste) coalition led by commander Prithviraj Chauhan at Tarain (near Delhi) in 1191, where he was defeated. The next year, he returned with 120,000 men against the Rajputs’ 300,000 (likely exaggerations). At the Second Battle of Tarain, he used his swift cavalry to break the Hindu forces by charging their center and scaring their elephants, winning decisively and killing their Chauhan.

After removing the main coalition against his rule in the fertile northern Indian heartland, Muhammad of Ghor’s armies swept over all of north India, reaching Bengal by 1200, and pretty much destroying Indian Buddhism en route. Most of India eventually came under Islamic rule, with the subsequent establishment of the Delhi Sultanate (1206) and the Mughal Empire (1526). This laid the groundwork for the future states of Pakistan and Bangladesh and strong empires like the Mughals that were able to unite most of South Asia. The largest concentration of Muslims in the world today is in South Asia.

Meanwhile, Hindus, who form the majority in the region reacted toward Muslim ruler in a variety of ways—resistance, collaboration, enmity, alliance. None of this was inevitable or even likely had the Muslims not won at Tarain.

Battle of Ain Jalut (1260)

This was the battle that stopped the previously unstoppable Mongol juggernaut and preventing them from advancing further in the Middle East, Africa, and Europe. Mongol armies clashed against a Mamluk force in modern day Israel in 1260, after destroying Baghdad in 1258. The Mamluks were a military caste of Muslim soldiers descended from slaves who had their base in Egypt. The Mongols were led by a secondary commander as their leader Hulagu Khan, grandson of Genghis Khan, had returned home due to a succession dispute. He was aiming to conquer the Levant and Egypt.

Both forces had over 20,000 men. However, the Mamluks defeated the Mongols using an old Mongol tactic, drawing them into an ambush. The Mamluk leader Qutuz, who had actually been captured by the Mongols and sold as a slave, hid most of his cavalry in the hills around the plain and ordered a small force forward in order to provoke a Mongol attack. This caused the Mongols to charge into the Mamluk trap. The battle marked the first time the Mongols were defeated in open battle.

The legacy of Ain Jalut was the fact that it preserved much of the Islamic World and Europe against further Mongol onslaught by preventing them from moving further west and proved that the Mongols could be beaten. Shortly after, the united Mongol front for world conquest fell apart and Mongols began fighting one another.

Battle of Cajamarca (1532)

The Battle of Cajamarca was fought in the Andes Mountains of modern day northern Peru between the Spanish under Francisco Pizarro and the Incas led by the Emperor Atahualpa. It was one of the weirdest battles in history because of the disproportionate numbers the two sides had.

Pizarro ventured deep into the heart of the Inca Empire with only 168 men in 1532, a number so small as to defy belief, especially since it seems like Pizarro’s plan was conquest from the beginning. Pizarro had studied the previous conquests of Hernan Cortes in Mexico, where that Spanish conquistador had defeated the much more numerous Aztec Empire with only a thousand men.

In order to defeat the Incas, he resorted to deceit and leveraging his advantages. Feigning benign intentions, he arranged to meet with Atahualpa, who brought 80,000 warriors to the meeting in the town square of Cajamarca (most were encamped outside the town). In a bold move, Pizarro captured the Atahualpa  and killed most of his major commanders with no loss to his men using his horses, guns, and steel to shock the Incas, who were not expecting a battle and who lost over two thousand men. The main Inca army was thrown into a rout and scattered.

Pizarro’s control over the Inca emperor led to his control of his empire, first through puppets and later directly. The destiny of most of a continent was sealed as a Spanish colony for the next three hundred years. The silver mined in Peru flooded the world market and led to the increased monetization of the world economy, in places as far away as Europe and China.