,  Manu , [ 25 ]   Parasara ,  Samvarta , Shankha ,  Shatatapa ,  Ushanasa ,  Vashishta ,  Vishnu ,  Vyasa ,  Yajnavalkya  and  Yama . These twenty-one rishis were the propounders of  Smritis . The oldest among these smritis are Apastamba, Baudhayana, Gautama, and Vasishta  Sutras . [ 26