72 Joseph E. InikoriThe other direct negative effect of the external slave trade on African
economic development is associated with the general socio-economic and socio-
political conditions created by the trade. Every economic activity has a way
of creating such conditions which not only help to sustain its earlier levels but
provide it with further momentum. This is the major idea behind Professor
Rostow's 'take-off' analysis. That self-reinforcing process was crucial in
sustaining the slave trade. The socio-economic and socio-political forces created
by the slave trade in Africa which sustained it for several centuries, operated
in the form of increased warfare based on the use of firearms and horses sup-
plied by the European and Arab slave-merchants, the emergence of professional
slave-raiders or man-hunters, the gearing of political, social and economic
institutions to the needs of slave acquisition and marketing and so on. The
incentives behind all these innovative activities were the increased variety of
European and Oriental products available to those with slaves to sell.
The mechanism of this self-sustaining process is well elaborated by many
writers on the slave trade. The account by Leo Africanus shows that the king
of Bornu (Borno) at the beginning of the sixteenth century sold slaves to
Barbary merchants and received horses for use in his cavalry in return. With
these horses the king carried out his annual slave-raiding expeditions.^47 The
horses may also have been used to acquire territorial fiefs through which
tribute slaves were obtained. In fact, the important slave market of Kuka is
said to have been supplied with slaves captured in government raids in the
surrounding non-Muslim territories south, west and south-west of Bornu
(Borno), and with tribute slaves paid by vassal princes who, in order to dis-
charge this obligation, carried on continuous warfare against their non-
Muslim neighbours.^48
In the Atlantic sector, firearms took the place of horses, and the prolifer-
ation of firearms in the coastal and forest states was an important part of the
self-reinforcing mechanism. The firearms gave steam to imperial ventures aimed
at controlling the sources of slave supply. The conflict between these nascent
empires over the control of slave supply on the one hand, and the need for
self-defence against their activities by their victims or potential victims on the
other hand, created a slave-gun circle. This is why it does not make much
sense to talk of these wars as being politically motivated, for beneath what
one may describe as a political motive lay what was primarily economic. This
is not to say that all the wars of the slave-trade period were caused by the con-
ditions created by the trade, nor that some non-economic motives were not
also present in wars that were largely due to the slave trade. But it does mean
that the self-reinforcing conditions created by the trade were responsible for
much of the wars of the period. As one writer puts it :
The two-way pressures of the ocean trade—European demand for captives and African