Kaya Alp
Kaya Alp was, according to Ottoman tradition, the son of Kızıl Buğa or Basuk and the father of Suleyman Shah or Gunduz Alp. He was the grandfather of Ertuğrul Ghazi and great-grandfather of the Ottoman Empire founder, Osman I. He was also famously known for being the successing name of Ertokus Bey's son Kaya Alp. He was a descendant of the ancestor of his tribe, Kayı son of Gun son of Oghuz Khagan, the legendary progenitor of the Oghuz Turks.