Alp Arslan (1029 15 December 1072) was the second sultan of the Seljuk dynasty and great-grandson of Seljuk, the eponym of the dynasty. He assumed the name of Muhammad bin Da'ud Chaghri when he embraced Islam, and for his military prowess, personal valour, and fighting skills he obtained the surname Alp Arslan, which means "a valiant lion" in Turkish.