Explanation: During the Battle of Carrhae, a major Roman defeat, the Romans had to endure a continuous rain of arrows from the Parthian horse archers. While Roman shields were somewhat effective against the continuous volleys, they couldn't hold out forever. The Roman commander, Crassus, supposed that it was simply a matter of waiting until the Parthians ran out of arrows, as arrow supply was a major issue in pre-modern warfare.
The Parthians, however, had planned for this, with a supply train of camels 1000 strong to bring arrows to the battlefield. The Romans were whittled away, and a massive army of legionaries destroyed by the power of C A M E L