 Gjon Kastrioti was among those who opposed the early incursion of Ottoman Bayezid I, however his resistance was ineffectual.The Sultan, having accepted his submissions, obliged him to pay tribute and to ensure the fidelity of local rulers, George Kastrioti and his three brothers were taken by the Sultan to his court as hostages.After his conversion to Islam, the young George Kastrioti attended military school in Edirne and led many battles for the Ottoman Empire to victory.