▁annual ▁t ribute ▁to ▁the ▁O man i ▁court ▁in ▁Mus cat . ▁During ▁his ▁ 1 4 - year ▁reign ▁as ▁Sultan , ▁Maj id ▁cons olid ated ▁his ▁power ▁around ▁the ▁local ▁slave ▁trade . ▁His ▁successor , ▁B arg hash ▁bin ▁Sa id , ▁helped ▁abol ish ▁the ▁slave ▁trade ▁in ▁Z anz ib ar ▁and ▁largely ▁developed ▁the ▁country ' s ▁infrastr ucture . ▁The ▁third ▁Sultan , ▁K hal ifa ▁bin ▁Sa id , ▁also ▁further ed ▁the ▁country ' s ▁progress ▁toward ▁abol ishing ▁sla very . ▁ ▁According ▁to ▁the ▁ 1 6 th - century ▁expl orer ▁Leo ▁African us , ▁Z anz ib ar ▁( Z ang ue bar ) ▁was ▁the ▁term ▁used ▁by ▁Arab s ▁and ▁Pers ians ▁to ▁refer ▁to ▁the ▁eastern ▁African ▁coast ▁running ▁from ▁southern ▁Som alia ▁to ▁northern ▁Moz amb ique , ▁domin ated ▁by ▁five ▁semi - in dependent ▁Muslim ▁kingdom s : ▁M omb asa , ▁Mal indi , ▁Kil wa , ▁Moz amb ique , ▁and ▁Sof ala . ▁African us ▁further ▁noted ▁that ▁they ▁all ▁had ▁standing ▁agre ements ▁of ▁loyal ty ▁with ▁the ▁major ▁central ▁African ▁states , ▁including ▁the ▁Kingdom ▁of ▁Mut apa . ▁ ▁Context ▁for ▁the ▁Sultan ' s ▁loss ▁of ▁control ▁over ▁his ▁domin ions ▁ ▁Until ▁ 1 8 8 4 , ▁the ▁S ult ans ▁of ▁Z anz ib ar ▁controlled ▁a ▁substantial ▁portion ▁of ▁the ▁Sw ah ili ▁Coast , ▁known ▁as ▁Z an j ,