New troop types, such as the "Thureophoroi" and the "Thorakitai", were developed. They used the Celtic "Thureos" shield, of an oval shape that was similar to the shields of the Romans, but flatter. The "Thureophoroi" were armed with a long thrusting spear, a short sword, and, if needed, javelins. While the "Thorakitai" were similar to the "Thureophoroi", they were more heavily armoured, as their name implies, usually wearing a mail shirt. These troops were used as a link between the light infantry and the phalanx, a form of medium infantry to bridge the gaps. Numerous armies used this form of troop, for example the Achaean League's armies before Philopoemen. By the end of the 3rd century BC, the 'Macedonian' phalanx had become the dominant fighting style even for states such as Sparta .