According to a cosmogonical story preserved in the "Vendidad", not long after Ahura Mazda had created the world, Angra Mainyu unleashed innumerable sicknesses upon it. In response, Ahura Mazda requested Manthra Spenta, Sraosha and Airyaman to find a cures for them, promising each that he would reward them and bless them with Dahma Afriti. With Airyaman's assistance, Ahura Mazda then brought 10,000 plants to the earth, so providing Thraetaona with the means to cure the world of all ills ("Vendidad" 22.5).