April 6, 2022 When the Mongols Set Out to Conquer the World, There Was Only One Limiting Factor: Grass IRAN / PERSIA.A cavalry battle. Armoured Mongols pursue fleeing foe. Rashid al-Din, Jami al-Tawarikh, c. 1305 CE. Full credit: Pictures from History / Granger, NYC — All rights reserved. When the Mongols Set Out to Conquer the World, There Was Only One Limiting Factor Grass