Assyrian army developed and evolved over time. In the Middle Assyrian period, foot soldiers were divided into the sạ bū ša kakkē ("weapon troops") and the sạ bū ša arâtē ("shield-bearing troops") but surviving records are not detailed enough to determine what the differences were. It is possible that the sạ bū ša kakkē included ranged troops, such as slingers (ṣābū ša ušpe) and archers (ṣābū ša qalte). The chariots in the army composed a unit of their own. Based on surviving depictions, chariots were crewed by two soldiers: an archer who commanded the chariot (māru damqu) and a driver (ša mugerre). Chariots first entered extensive military use under Tiglath-Pileser I in the 12th–11th centuries BC and were in the later Neo-Assyrian period gradually phased out in favor of cavalry (ša petḫalle). In the Middle Assyrian period, cavalry was mainly used for escorting or message deliveries. Under the Neo-Assyrian Empire, important new developments in the military were the large-scale introduction of cavalry, the adoption of iron for armor and weapons, and the development of new and innovative siege warfare techniques. At the height of the Neo-Assyrian Empire, the Assyrian army was the strongest army yet assembled in world history. The number of soldiers in the Neo-Assyrian army was likely several hundred thousand. The Neo-Assyrian army was subdivided into kiṣru, composed of perhaps 1,000 soldiers, most of whom would have been infantry soldiers (zūk, zukkû or raksūte). The infantry was divided into three types: light, medium and heavy, with varying weapons, level of armor and responsibilities. While on campaign, the Assyrian army made heavy use of both interpreters/translators (targumannu) and guides (rādi kibsi), both probably being drawn from foreigners resettled in Assyra. Population and society Population and social standing Populace The majority of the population of ancient Assyria were farmers who worked land owned by their families. Old Assyrian society was divided into two main groups: slaves (subrum) and free citizens, referred to as awīlum ("men") or DUMU Aššur ("sons of Ashur"). Among the free citizens there was also a division into rabi ("big") and ṣaher ("small") members of the city assembly. Assyrian society grew more complex and hierarchical over time. In the Middle Assyrian Empire, there were several groups among the lower classes, the highest of which were the free men (a’ılū), who like the upper classes could receive land in exchange for performing duties for the government, but who