Mechanical devices that could hurl projectiles, namely darts or stones, were known as catapults and ballistas in Antiquity. The product of reflections on how to mechanise the bow to increase its force, siege machines first appeared in the early 4th century BC, in Syracuse. This apparatus harnessed the energy built up by twisting skeins of elastic fibres - sinews, horsehair and female hair were much prized for this purpose. More effective than tension siege engines, these devices could hurl projectiles at great speed and distances.