who did not have plots to tend at home and were attracted by the modest military pay and the prospect of a share of war booty. The minimum property requirement for service in the legions, which had been suspended during the Second Punic War, was effectively ignored from 201 BC onward in order to recruit sufficient volunteers. Between 150 BC and 100 BC, the manipular structure was gradually phased out, and the much larger cohort became the main tactical unit. In addition, from the Second Punic War onward, Roman armies were always accompanied by units of non-Italian mercenaries, such as Numidian cavalry, Cretan archers, and Balearic slingers, who provided specialist functions that Roman armies had previously lacked. Roman army of the late Republic (88–30 BC) The Roman army of the late Republic (88–30 BC) marks the continued transition from the conscription-based citizen levy of the mid-Republic to the mainly volunteer, professional standing forces of the imperial era. The main literary sources for the army's organisation and tactics in this phase are the works of Julius Caesar, the most notable of a series of warlords who contested for power in this period. As a result of the Social War (91–88 BC), all fellow Italians were granted Roman citizenship, the old allied alae were thereby abolished and their members integrated into the legions. Regular annual conscription remained in force and continued to provide the core of legionary recruitment, but an ever-increasing proportion of recruits were volunteers, who signed up for 16-year terms as opposed to the maximum 6 years for conscripts. The loss of ala cavalry reduced Roman/Italian cavalry by 75%, and legions became dependent on allied native horse for cavalry cover. This period saw the large-scale expansion of native forces employed to complement the legions, made up of numeri ("units") recruited from tribes within Rome's overseas empire and neighbouring allied tribes. Large numbers of heavy infantry and cavalry were recruited in the Roman Provinces of Hispania, Gallia and Thracia, and archers from the Eastern Mediterranean, (mostly from Thrace, Anatolia and Syria). However, these native units were not integrated with the legions, but retained their own traditional leadership, organisation, armour and weapons. Imperial Roman army (30 BC–AD 284) During this period, the Republican system of citizen conscription was replaced by a standing professional army of mainly volunteers serving standard 20-year terms (plus five years as reservists), although many in the service of