From left to right: A thin pilum,
thick pilum, and weighted pilum.
The Pilum (Spear)
When Swords wouldn't do, Roman soldiers relied on the pilum, which was a long spear, or javelin. There were two types: think and thin. The thin one had a long iron head, that fit to the long handle by way of a socket. The thin pilum was about 2 m long, with a barbed point. The thick pilum was of similar length, and was attached to the shaft with a 5 cm wide tang. The tip of both of these weapons had a pyramid-shaped barb. The shaft of both was about 7.5 mm in diameter. On the thick pilum was a wooden block to secure the metal head. The block also protected the hand in melee fighting. Soldiers carried both types of spear.
Later versions of the pilum in the first century were constructed similarly, but the thick pila were much lighter, weighing in at about 2kg. This lightening of the pilum led to the introduction of a version of the heavy pilum with a weighted ball at the top of the shaft, to help balance the spear. The point was made of softer iron so that it would bend upon impact, preventing the enemy from throwing the spear back.
The pilum could either be thrown, or used in hand to hand combat. It was usually thrown before engaging the enemy with swords.