Ralph Payne-Gallwey, A summary of the history, construction and effects in warfare of the projectile-throwing engines of the ancients with a treatise on the structure…
“ If the knowledge of constructing the great catapult of the ancients in its original perfection had been retained, such a clumsy engine as the mediæval trebuchet would never have gained popularity. The trebuchet derived its power from the gravity of an immense weight at one end of its pivoted arm tipping up the other end, to which a sling was attached for throwing a stone. ”
