A dervish counted among the caliphs (halife) of Hacı Bektâş-ı Velî; he appears in the Vilâyetnâme as Baba Resul / Resul Baba. His domed tomb (kümbet) stands within the Hacı Bektâş-ı Velî complex, abutting the eastern wall of the main shrine and opening onto Kırklar Meydanı, and is among the oldest units of the complex. According to Remzi Gürses, its gravestone is dated 677 (1278-79). (Sources: TDV İslâm Ansiklopedisi, 'Hacı Bektâş-ı Velî Külliyesi'; Remzi Gürses, Hacıbektaş Rehberi.)