I believe the first crusade began due to Emperor Alexios of the byzantines , requesting aid from the pope to defeat the turkish barbarians ... ( not sure) the pope decided to send around 60,000 soldiers not to aid the byzantines but rather to conquer jerusalem through the byzantine empire . My question is what happened after they finally conquered it (Jerusalem) . In other words what were consequences of the first crusade ? Also if possible : what were the results/ consequences of the crusades as a whole and why did the crusades suddenly end after over 200 years of fighting ?
Starting with the last bit and working back - 200 years of fighting doesn't describe the situation accurately. There were periods of strife interleaved with peace.
The first crusade in 1099 resulted in the creation of the Kingdom of Jerusalem. This was short-lived but had an effect specifically on the architectural legacy of the city of Jerusalem.
Each crusade was different in character, leadership and management. All have in common an underlying role in underpinning a political construct in western Europe eg the Papacy or the Holy Roman Emperor.
the consequences of the crusades are still with us, eg George W Bush calling for a crusade, which convinced much of the Muslim world that America wanted to wipe Islamic countries out. I still don't know if he just spoke clumsily, as he often did, or if he really meant it and they were right.
The first crusade was the only militarily successful one (though the sixth achieved a great deal by treaty). Gradually, Europeans just lost interest as subsequent crusades failed.
Not all crusades involved the Holy Land and fighting the moslems. Pope Innocent III wasn't happy that the christian Cathars of southern France refused to come under the cloak of Rome, and declared a crusade against them that lasted 20 years...