The first of the four planned Crusader armies arrives in Constantinople, at this time ruled by Alexios I Komnenos. This first army is under the command of Hugh of Vermandois, younger son of King Henry I of France, and his forces have arrived first because they crossed the Adriatic Sea by boat rather than travel overland like the other armies.
Hugh's older brother and future king of France, Philip, is not allowed to participate in the Crusade because he has been excommunicated. Thus Hugh has been given command of France's Crusading army; unfortunately, he is neither a good military commander nor a good leader generally.
When he arrives, Alexius I has Hugh held in a monastery until he swears vassalage to him.