What were the crusaders exactly?

Answer 1

They were the popes army(donated by many countries) who fought to reclaim the Holy Land after it was taken over by the muslims.

The most famous order were the knights templar who also invented banking.

Answer 2

The Crusades were a series of military campaigns of a religious character waged by Christians from 1095-1291, usually sanctioned by the Pope in the name of Christendom,[1] with the goal of recapturing Jerusalem and the sacred "Holy Land" from Muslim rule and originally launched in response to a call from the Eastern Orthodox Byzantine Empire for help against the expansion of the Muslim Seljuq dynasty into Anatolia.[2][3]

The term is also used to describe contemporaneous and subsequent campaigns conducted through the 16th century in territories outside of the Levant[4], usually against pagans[citation needed] and those considered by the Catholic Church to be heretics, for a mixture of religious, economic, and political reasons.[5] The traditional numbering scheme for the Crusades includes the nine major expeditions to the Holy Land during the 11th to 13th centuries. Other unnumbered "crusades" continued into the 16th century, lasting until the political and religious climate of Europe was significantly changed during the Renaissance and Reformation.

Answer 3

In Primogeniture the first son inherits the title, the land etc.
Either the second son gets appointed to the church or I'm confusing that with the third son.
The third son and any more sons, get a suit of armor, a war horse, and training. They are expected to find their own fortune.

This provide ulterior motives for the taking of lands and the sacking of Constantinople.

Answer 4

European soldiers who went to arabia to recapture Jerusalem from muslims.