Crusades were military campaigns sanctioned by the Catholic Church during the Middle Ages, to expand the realm of Christianity or to put down heresies within it. They have also inspired numerous dramatic works in the literature of Christian Europe.

King Eric IX of Sweden and bishop Henry en route to Finland in the late medieval depicion from Uppland.

The Crusades most commonly refers to the nine crusades to the Holy Land from 1095 to 1272; those are the topic of this article. Other crusades include Northern Crusades to Balticum and Finland, the Abligensian Crusade against the Cathars of what is now southern France, the Reconquista taking the Iberian Peninsula back from the Moors, and several crusades against the Hussites of Bohemia.

While the headline summation is "Roman Catholic Europeans going to the Holy Land to conquer" and it is relatively well known that a speech by Pope Urban II in 1095 launched the first crusade, the actual history is much more complicated. Pilgrimage to the sites of the life of Jesus of Nazareth had been a Christian tradition at least since the trip of Emperor Constantine's Christian mother to Jerusalem in the 4th century where she claims to have found the "True Cross of Christ" (splinters of which would later add up to a veritable forest of crosses). See Jesus Trail for some of the pilgrimage routes.

With the Byzantine Empire fighting an on again off again war against Muslim adversaries to the East, the rulers in Constantinople started toying with the idea of asking the Christians to their west to aid them in defeating the "heathens" to their east. Reports of pilgrims being harassed and even a desecration of Holy Sites further fueled the desire by Europeans to take revenge for real or perceived wrongs.

Destinations

• 1 Rome.  
• 2 Constantinople (later called Istanbul). capital of the Byzantine Empire  
• 3 Levant. The main region where the Crusades took place  

The Crusaders created numerous states of varying longevity. The nominal claim to the Kingdom of Jerusalem was maintained in the long form titles of several monarchs into the early modern period. Indeed, some crusades served mainly to help out a Crusader state in need.

In "Outremer" as the Crusader territories came to be collectively known there were often tensions between Catholic new arrivals and Jewish and Muslim inhabitants but also sometimes the non-Catholic Christians who did not mind their erstwhile Muslim rulers but did not like being bullied around for "doing Christianity wrong".

The Holy Land

• 4 Jerusalem. A holy city for Jews and Muslims as well as Christians.  
• 5 Acre. Now called Akko, was a Crusader city and still has some of their buildings  
• 6 Antioch. As of a few hundred CE, this was the 4th largest city in the Roman Empire and a major center of early Christianity.  
• 7 Sidon (Saida). An ancient Phoenician city whose main tourist attraction today is its 13th century crusader castle.  

Crusader orders

There were several orders of Catholic warrior monks. They built castles and left behind ruins in many places.

• Knights Templar (Poor Fellow-Soldiers of Christ and of the Temple of Solomon). This order's original mission was to protect Christian pilgrims in the Holy Land from bandits and Muslim raiders. Headquarters was on Temple Mount in Jerusalem. They also had a large presence in Acre and fought a desperate battle there in 1291 protecting Christians trying to escape as the Kingdom of Jerusalem fell.
  There are Templar sites in many parts of Europe; see Wikipedia for a list. Two of the most interesting are the Portuguese town of Tomar, mostly built by the order, and a Templar museum in Arville, France.
  The order became quite rich and powerful, and was eventually destroyed by the French King, who owed them a huge amount and did not want to pay, with the collusion of an Avignon Pope. Their last Grand Master, Jacques de Molay, was executed in 1314 on the Île aux Juifs in Paris.  
• Knights Hospitaller (Order of Knights of the Hospital of Saint John of Jerusalem). This order was dedicated to providing medical care. As the fortunes of the Crusades waned, their headquarters were moved from Jerusalem to Cyprus, Rhodes, and eventually Malta which they ruled 1530-1798. The Sovereign Military Order of Malta also claims continuity from the Knights Hospitaller.  
• Teutonic Knights (Order of Brothers of the German House of Saint Mary in Jerusalem). This was a smaller order that both protected pilgrims and ran hospitals. Headquarters was in Acre. Later they were active in the Northern Crusades and in various campaigns to expand German influence east, notably into Poland.  

See also

• Christianity, Islam, Judaism
• Assassin's Creed Tour
• Indiana Jones tourism; concerning Indiana Jones and the Last Crusade
• Islamic Golden Age
• Medieval Britain and Ireland
• The overland itinerary from Istanbul to Cairo connects to numerous Crusader castles in the Levant.
• Robin Hood, a legendary English folk hero during King Richard's crusade, in some works described as a crusader himself