<P> Following his defeat, Dingane burned his royal household and fled north . Mpande, the half - brother who had been spared from Dingane's purges, defected with 17,000 followers, and, together with Pretorius and the Voortrekkers, went to war with Dingane . Dingane was assassinated near the modern Swaziland border . Mpande then took over rulership of the Zulu nation . </P> <P> Following the campaign against Dingane, in 1839 the Voortrekkers, under Pretorius, formed the Boer republic of Natalia, south of the Tugela, and west of the British settlement of Port Natal (now Durban). Mpande and Pretorius maintained peaceful relations . However, in 1842, war broke out between the British and the Boers, resulting in the British annexation of Natalia . Mpande shifted his allegiance to the British, and remained on good terms with them . </P> <P> In 1843, Mpande ordered a purge of perceived dissidents within his kingdom . This resulted in numerous deaths, and the fleeing of thousands of refugees into neighbouring areas (including the British - controlled Natal). Many of these refugees fled with cattle . Mpande began raiding the surrounding areas, culminating in the invasion of Swaziland in 1852 . However, the British pressured him into withdrawing, which he did shortly . </P> <P> At this time, a battle for the succession broke out between two of Mpande's sons, Cetshwayo and Mbuyazi . This culminated in 1856 with the Battle of Ndondakusuka, which left Mbuyazi dead . Cetshwayo then set about usurping his father's authority . When Mpande died of old age in 1872, Cetshwayo took over as ruler . </P>

Which of the following was an important cause for the rise of the zulu kingdom of southern africa