Most of the crusaders insisted that Jerusalem must take precedence, promising to attend to Edessa once the Holy City had been freed. Baldwin, however, agreed to go. This caused much consternation among the crusaders, who said they needed every knight they could get, but Baldwin was determined.
So, he turned aside from the main crusading army, and freed the city, and was adopted by the grateful Christian ruler. Within months, however, Baldwin had deposed the count and claimed the title for himself, which he very likely had planned to do from the first.
Thus the County of Edessa became the first of the crusader states, and Baldwin of Boulogne its first ruler. Although he had promised to go to Jerusalem as soon as he had liberated Edessa, he in fact did not go until after Jerusalem had fallen to the crusaders. Baldwin is one of the clearest examples we have of a knight who went on the First Crusade in order to win lands for himself.