Each legion was normally partnered with an approximately equal number of allied (non-Roman) "auxiliae" troops. The addition of allied troops to the Roman army was a formalisation of the earlier arrangement of using light troops from the Socii and Latini, who had received Roman citizenship after the Social War. Auxiliary troops could be formed from either auxiliary light cavalry known as "alae", auxiliary light infantry known as "cohors auxiliae", or a flexible mixture of the two known as "cohors equitata". Cavalry types included mounted archers (Latin: "sagittarii") and heavy shock cavalry (Latin: "cataphracti" or "clibanarii"). Infantry could be armed with bows, slings, throwing spears, long swords, or thrusting spears. Auxiliary units were originally led by their own chiefs, and, in this period, their internal organisation was left to their commanders.