<P> In 1988, Rhodes University professor Julian Cobbing advanced a controversial new hypothesis on the rise of the Zulu state; he contended the accounts of the Mfecane were a self - serving, constructed product of apartheid politicians and historians . According to Cobbing, apartheid historians had mischaracterised the Mfecane as a period of internally induced black - on - black destruction . Instead, Cobbing argued that the roots of the conflicts could be found exclusively in the labour needs of the Portuguese slave traders operating out of Delagoa Bay, in modern - day Mozambique, and of the British colonists in the Cape . The resulting pressures led to massive displacement, famine, and war in the interior, allowing later Afrikaner settlers to seize control of most land . Among those involved were European adventurers such as Nathaniel Isaacs (who was later accused of slave trading) </P> <P> Cobbing's hypothesis (now known by many historians as the "Cobbing Controversy") remains controversial . Many agree that Cobbing's analysis offered several key breakthroughs and insights into the nature of early Zulu society . Some critics assert that revisionist theories such as Cobbing's placed too much weight on environmental factors and ignored the key roles played by dynamic human agents such as the Zulu king Shaka . The historian Elizabeth Eldredge challenged Cobbing's thesis on the grounds that there is scant evidence of the resumption of the Portuguese slave trade out of Delagoa Bay before 1823, a finding that undermines Cobbing's thesis that Shaka's early military activities were a response to slave raids . Moreover, Eldredge argues that Griqua and other groups, rather than the British colonists, were primarily responsible for the slave raids coming from the Cape . Eldredge also asserts that Cobbing downplays the importance of the ivory trade in Delagoa Bay, and the extent to which African groups and leaders sought to establish more centralised and complex state formations to control ivory routes and the wealth associated with the trade . She suggests these pressures created internal movements, as well as reactions against European activity, that drove the state formations and concomitant violence and displacement . </P>

What were age regiments used for by chiefs