The People's Crusade of 1096 had been a well-meaning bust, so it was time for the real army to swing into action.  And even though it was really the "second" crusade, it's called the "first."

Knights and princes - experienced, battle-hardened warriors - led a series of campaigns against the infidel Turks to conquer the Holy Land for the Christian cause.  The first of these 'official' campaigns was named, not surprisingly, the First Crusade (1096-1099).

The goal of the First Crusade - retaking Jerusalem and most of the Holy Land for Christianity - had been achieved. No future crusade would enjoy as much success.  But more blood was to be spilled. During the next two centuries, the original conquests in the Holy Land, including Jerusalem, were gradually lost.