he astern ▁Africa ▁arrived ▁around ▁ 1 0 0 0   AD . ▁South ▁Indian ▁T amil ▁mer ch ants ▁arrived ▁around ▁ 1 1 th ▁century . ▁They ▁introduced ▁the ▁z eb u , ▁a ▁type ▁of ▁long - horn ed ▁hum ped ▁cattle , ▁which ▁they ▁kept ▁in ▁large ▁her ds . ▁Ir rig ated ▁p addy ▁fields ▁were ▁developed ▁in ▁the ▁central ▁high land ▁B ets ile o ▁Kingdom ▁and ▁were ▁extended ▁with ▁ter rac ed ▁p add ies ▁throughout ▁the ▁neighbor ing ▁Kingdom ▁of ▁I mer ina ▁a ▁century ▁later . ▁The ▁rising ▁intensity ▁of ▁land ▁cultiv ation ▁and ▁the ▁ever - in cre asing ▁demand ▁for ▁z eb u ▁past ur age ▁had ▁largely ▁transformed ▁the ▁central ▁high lands ▁from ▁a ▁forest ▁e cos ystem ▁to ▁grass land ▁by ▁the ▁ 1 7 th ▁century . ▁The ▁or al ▁histor ies ▁of ▁the ▁Mer ina ▁people , ▁who ▁may ▁have ▁arrived ▁in ▁the ▁central ▁high lands ▁between ▁ 6 0 0 ▁and ▁ 1 , 0 0 0 ▁years ▁ago , ▁describe ▁encounter ing ▁an ▁established ▁population ▁they ▁called ▁the ▁V az im ba . ▁Probably ▁the ▁descend ants ▁of ▁an ▁earlier ▁and ▁less ▁techn olog ically ▁advanced ▁Aust ron esian ▁settlement ▁wave , ▁the ▁V az im ba ▁were ▁assim il ated ▁or ▁exp elled ▁from ▁the ▁high lands ▁by ▁the ▁Mer ina ▁k ings ▁And ri am anel o , ▁R al am bo ▁and ▁And rian j aka ▁in ▁the ▁ 1 6 th ▁and