The "Prince's Crusade", gradually made its way to Constantinople, led in sections by Godfrey of Bouillon, Bohemond of Taranto, Raymond IV of Toulouse, and other important members of the western nobility. Alexios used the opportunity to meet the crusader leaders separately as they arrived, extracting from them oaths of homage and the promise to turn over conquered lands to the Byzantine Empire.

Transferring each contingent into Asia, Alexios promised to supply them with provisions in return for their oaths of homage. The crusade was a notable success for Byzantium, as Alexios recovered a number of important cities and islands. The siege of Nicaea by the crusaders forced the city to surrender to the emperor in 1097, and the subsequent crusader victory at Dorylaeum allowed the Byzantine forces to recover much of western Asia Minor.

John Doukas re-established Byzantine rule in Chios, Rhodes, Smyrna, Ephesus, Sardis, and Philadelphia in 1097–1099. This success is ascribed by Alexios' daughter Anna to his policy and diplomacy, but by the Latin historians of the crusade to his treachery and deception.