āsīd vaivasvato manuḥ

sah-he; tu-indeed; satyavratah-Satyavrata; raja-the King; jnana-vijnana-samyutah-enlightened in full knowledge and its practical use; visnoh-of Lord Visnu; prasadat-by the mercy; kalpe asmin-in this period (ruled by Vaivasvata Manu); asit-became; vaivasvatah manuh-Vaivasvata Manu.