John Komnenos (Greek: Ἰωάννης Κομνηνός, romanized: Iōannēs Komnēnos), later surnamed Tzelepes (Τζελέπης, Tzelepēs), was the son of the sebastokrator Isaac Komnenos and grandson of the Byzantine emperor Alexios I Komnenos. As a young man he followed his father during his exile and wanderings across Asia Minor and the Levant, when for a short time he was married to a daughter of Leo I, ruler of Armenian Cilicia. After the reconciliation between his father and his uncle, Emperor John II Komnenos, in 1138, he returned to the Byzantine court, but defected in the next year to the Danishmendid Turks during a siege of Neocaesarea. From there he moved to the court of the Sultan of Rum, one of whose daughters he married. According to later, and likely invented, tradition, the Ottoman dynasty hailed from one of his offspring.