While the heavy pilum was the signature javelin of the Roman legionary, the auxiliary troops relied on a different, more versatile weapon: the lancea. This lighter javelin served as a key piece of equipment for the non-citizen soldiers who supported the legions.

The lancea was built for practicality. It consisted of a short wooden shaft, typically around 2 meters (about 6.5 feet) long, tipped with a small, leaf-shaped iron head. This design made it light enough to be thrown a considerable distance but sturdy enough to be used in hand-to-hand combat if necessary.

Unlike the pilum, which was designed to bend and become unusable after a single throw, the lancea was a reusable weapon. An auxiliary could carry several into battle. Its primary function was to be hurled at the enemy from a distance to disrupt their formations before a charge. However, its balanced design and solid construction also made it a capable thrusting spear in close quarters, a flexibility the pilum lacked.

The Roman army used a variety of polearms, and it's easy to confuse them. The lancea stands out for its specific role and users. It was the multi-purpose javelin of the auxiliaries, distinct from the legionary's heavy pilum and the dedicated thrusting spear, the hasta.

The soldiers who wielded this weapon were known by a specific name.

As the Roman military evolved, the lancearii became more common, especially in the later empire. Their flexible fighting style, combining ranged attacks with close-combat capability, proved valuable on many battlefields.

The lancea equipped Rome's auxiliary forces with a reliable and adaptable weapon, proving that the army's strength lay not just in its legions, but in its supporting troops as well.