The Crusades still stir up debates today.

Both sides, East and West, Christians and Muslims, went to war over religion, each claiming they were doing so in the name of peace and all that was holy. Each side attacked and each side killed the other’s soldiers.

In Western history, the Christians are often seen as the side that was “defending” their territory. And, for example, when former President Barack Obama mentioned the atrocities carried out by Christians, he was accused of belittling Christianity. But we know for a fact that Christian Crusaders did kill Jews, Muslims, Byzantine Greeks, and many others and were no more peaceful than the Muslims they went to war with.

Muslims had been in control of Jerusalem for centuries. But as they expanded, the Pope became even more concerned that they were threatening Christian villages. But as he tried to drum up support for his First Crusade in 1095, he spoke harshly about all non-Christians, including Jews.

In fact, the speech riled up soldiers who committed waves of massacres against Jews in what is now France and Germany. And even when Jerusalem was recaptured, the Christians forced the Jews to surrender as well, or face execution.

The Crusades took place over the course of 200 years, and estimates of the death toll range from 1 million to 9 million people. Looting and ransom also helped fund the Papacy, which amassed wealth and power during time.

In addition, in some places, remnants of feudalism were swept away, even wiping out many prominent noble family lines (though this was the result of multiple influences).

European countries also had the desire to expand further, spreading their influence all the way to the New World.

But this was also a time that people used trade routes not only for war, but for the spread of mathematical, scientific, architectural, and historic knowledge as cultures mingled in less violent ways as well.

In other words, the Crusades played a role in big changes on at least 5 continents.

We have only fragments of knowledge about the Children’s Crusade, but it was likely the first youth movement in European history.

While it wasn’t officially a Church-sanctioned Crusade, the event apparently took place in 1212 and involved children in France and Germany who were inspired by the preaching they heard to join the Crusades and decided to take matters into their own hands.

There are many references to it in historical documents, but none of them are complete. It may not have even involved young children. But with the kind of sentiment being whipped up all around Europe and the fact that the Fifth Crusade began shortly after, it’s certainly not impossible.

Women were heavily involved in The Crusades. Wives took control of the family estates as the men marched off to war.

Others joined Crusaders on the march as camp followers and nurses, with even prominent noblewomen lending their time to the effort, despite being discouraged by the popes to do so (since they were assumed to be a distraction).

The death of noblemen also meant lands and possessions were left to wives if there was no other choice. Cultural inheritance in Europe often meant sons were heirs, but with so many men dead, that norm was disrupted.

Two hundred years of Crusades were bound to be associated with many great thinkers and leaders on both sides.

Names like King Richard I of England (aka Richard “The Lionheart”, Eleanor of Aquitaine of France, Saladin, Frederick Barbarossa, King Edward I of England (a.k.a. Longshanks), and numerous prominent popes will be forever linked to the Crusades.

The call for the Ninth Crusade went mostly unanswered as European kingdoms were busy fighting amongst themselves. In addition, the Mongols became a threat to both sides, even forcing some cooperation.

In 1271m England, France, and other kingdoms launched a force to retake Jerusalem one last time. By 1303, Muslims controlled the Holy Land in Jerusalem, and The Crusades as we know them were over.

The Mongols posed a threat to both sides, but in 1242 the Christians actually tried to form an alliance with them after Ogedai Khan, the son and successor of Genghis, passed away.

A Franco-Mongol alliance was proposed to take Jerusalem back from the Muslims.

Pope Innocent IV sent the monk John of Plano Carpini to the Karakorum with a letter asking for assistance in dealing with the Muslims, but the new Khan, Guyuk, demanded that the Pope submit to Mongol rule.

That’s was obviously never going to happen, so the alliance never took place. The Mongols went on to wage war against the Muslims themselves.

Louis IX of France called for another Crusade as he was defeated in the Seventh. This Eighth Crusade – that others consider an extension of the Seventh – just adds to the confusion as the Ninth was called an extension of the Eighth.

In 1244, the different Muslim empires began to form alliances to take back the Holy City of Jerusalem together, which was already weakly defended.

Most of Europe was too preoccupied with their own events, and not even the Papacy took notice.

This led King Louis IX of France to mount the Seventh Crusade but his efforts ended in complete disaster for both he and his men.

The Sixth Crusade was launched after the Christians’ failure in the Fifth.

However, this one wasn’t as bloody as the others since Holy Roman Emperor Frederick II managed to negotiate with his counterpart Al-Kamil to regain control over some areas of Jerusalem.

While most of Israel was now under Christian control, Muslims stayed in possession of the Temple Mount, the al-Aqsa mosque, and the Dome of the Rock. Frederick entered the city a month after the treaty was cemented in February 1229.

Pope Innocent III and his successor made plans for another Crusade to take Jerusalem back.

German, Hungarian, Austrian, French, and Holy Roman Empire knights left for the Holy Land in 1213 but not before attacking Egypt as a precursor to taking Jerusalem.

But forces led by Al-Malik al-Kamil, the nephew of Saladin crushed the coalition. Al-Kamil agreed to return a piece of the True Cross after a truce was made. But he didn’t really have the piece – he was just using it as a bargaining chip instead.

The third call for a Crusade went out when the Pope found out that Saladin had retaken Jerusalem.

King Henry II of England and Phillip II of France began building a new army, but when Henry died soon after, Richard I (aka Richard The Lionheart) took his place. Together with Fredrick Barbarossa, the kings looked to retake Jerusalem.

But Fredrick didn’t wait for the others, giving his armies the order to attack. They were successful at first but then drowned crossing a river. Most of Barbarossa’s men headed back to Germany before the arrival of French and English armies.

The Third Crusade saw plenty of other interesting moments as well, such as Saladin’s brother sending Richard I a new horse when he saw his was wounded.

But eventually, Saladin launched an enormous attack. Alas, he was beaten at Jaffa and negotiated a peace settlement. Jerusalem stayed under Muslim control after a truce was reached.

The Fourth Crusade of 1202 saw crusaders from Venice, the Holy Roman Empire, and the Kingdom of France laying siege to Constantinople. The city was left in ruins.

Pope Innocent III rebuked the Crusaders, though he still received all the loot they brought back.

Greek and Roman Catholic Christians were split in two after the bloody conflict, and a schism between Eastern Orthodox Christianity and the Vatican developed.

In 1187, Muslim leader Saladin took the Kingdom of Jerusalem.

Saladin’s army crushed the Crusader army at the Battle of Hattin and Saladin then laid siege to Jerusalem in September.

In October, the city was surrendered to Saladin by Balian of Ibelin.

Fun fact: Ridley Scott’s 2005 film Kingdom of Heaven (starring Orlando Bloom and Liam Neeson) dramatized the events of 1187.

Pope Urban made his appeal to launch the First Crusade, but he would live less than a year after doing so, never seeing his requests met.

He died on July 29, 1099.

Jerusalem had fallen two weeks earlier, and news hadn’t reached Rome or the Pope yet.

A number of pilgrims chose to turn back, and some did not even leave Europe at all.

The First Crusade ended up being a success, ending in mockery and derision for those who went back.

Many of those who turned back ended up joining the Crusade of 1101 (also called the Crusade of the Faint-Hearted). They left Constantinople, constantly harassed by Turkish forces, before their defeat at the Battle of Mersivan in northern Turkey. The Crusaders were finished off in two other battles.

Four Roman-Catholic “Crusader states” were formed in 1099 they took Jerusalem.

Crusaders established territories to convert residents and extend the Church’s influence and power overseas.

The architecture in those areas is an interesting combination of different cultural traditions.

There was a People’s Crusade before the actual First Crusade.

Peasants and priests, minor knights, and even women, children, and monks went to Jerusalem, led by charismatic monk Peter the Hermit.

They were untrained and easily defeated by the Seljuk Turks. Peter the Hermit’s followers were wiped out at the Battle of Civetot with only a few thousand making it to Constantinople.

They were, however, responsible for the massacre of Jews along the way.

Before the Crusades, noblemen often fought each other, leading to constant chaos throughout Europe. Then, a movement called the Peace of God laid down some rules. One was that church property, women, children, the elderly, and other non-combatants were off-limits to fighters.

In the 11th century, the Truce of God was added to the Peace of God. That further limited the days of fighting (Lent, Advent, Fridays, and Saturdays).

The Peace of God and Truce of God were seen as failures, though they helped re-establish order in western Europe. Eventually, the knights would direct their lust for conquest at the Muslims instead of each other.