Answer:
The Crusaders didn't had unified leadership and would even quite often fight between each other.
The true reasons for Crusades were the spreading of power and gaining of territories and not the freeing the Holy Land.
They were surrounded by enemies, who were constantly attacking them.
Explanation:
When the Crusades started in the second half of 11th Century reasons were totally different than what they proved to be. Although Crusaders were saying that they are going to deliberate the Holy Land what actually was shown is that the greed is the main reason.
Crusaders had no mutual coordination, quite frequent quarreled and that is why at the end were defeated. One of the important things also that should be mentioned is the problem of provisions that were coming from Europe.
