Sikh religion was founded conjointly by the great teachers or gurus: the line began with guru Nānak (A.D. 1469-1538) and ended with guru Govind Singh (A.D. 1666-1708). Sikh philosophy is contained in the religious, poetic compositions (Gurbāṇī) of guru Nānak —it is expounded in the hymns (śabads) of the other nine gurus and elucidated in the ballads (vārs) of a learned, devout Sikh, Bhai Gurdās.