Pope Urban II calls the population in Clermont (France) in 1095: Muslims have taken the Holy Land, the population has to fight to take it back. The people are all excited, social ranks do not even matter.
It is then in 1095 that thousands of people, including wife, children and elder people, decided to leave for the Holy Land. they experienced the heat and the cold, the thirst, the starvation and the death, to get to Antioch, and then to Jerusalem.
the second, third and fourth crusades are characterized by the loss of Jerusalem from the Christians to the Muslims.
In 1212, children were sent to Jerusalem, because people thought that children would manage to take Jerusalem back, as they were thought to be Holy. At the end, they were sold as slaves. the Fifth Crusade took place from 1217 to 1221. It was failure.
Both the fifth and the sixth crusades are failures. Even though the fifth one was not at first because of the traity of Jaffa that stated that Jerusalem was the Christian's, it was refuted by the population who felt that it was a treason.
Starting in 1267 by accumulating weapons and foods, Louis IX left for Tunis in 1270. However, he ended up dying there, before even fighting... This tragic episode ended this era of crusades.