Population movements between East Africa,
and the neighbouring countries177cultures of Asia and the Middle East? These and other similar questions need
to be explored.
Moving on to the nineteenth century, we find that the historians' main
concern has been the volume of the slave trade. Scholars such as R. P. Baur,
R. W. Beachey and Richard Rensch maintain that several millions of East
Africans were sold into slavery in the nineteenth century. Baur, for instance,
asserts that 30,000 slaves were exported from the East African coast annually
in the 1880s.^13 Professor Beachey affirms that over 5 million east Africans were
sold into slavery during the nineteenth century.^14 Three doctoral theses have
recently shown that the above estimates were nothing but wild guesses.^15
Before we can engage meaningfully in a quantitative discussion of the
Indian Ocean slave trade, we should emphasize that before the nineteenth
century, the majority of slaves were household servants, artisans, soldiers,
sailors, common labourers and concubines. They rarely engaged in large-scale
production of commodities. (The only known exceptions are the salt works of
Persia in the ninth century and salt mines in the Sahara). The expansion of
commerce in the late eighteenth and early nineteenth centuries gradually
transformed agriculture in eastern Africa. More and more land was brought
under cultivation between 1820 and 1870. Traders became farmers, and slave-
traders became slave-owners. A slave system fradually emerged in East Africa,
in which the ownership of the means of production—land and slaves—defined
the principal social groups in society.
The development of European sugar plantations in the islands of Bourbon
and Ile de France relied on slave labour. The slave population of Bourbon grew
from 387 in 1808 to 30,000 in 1779 and 50,000 in 1809-10, while that of Ile de
France rose from 19,000 in 1766 to 55,000 in 1809-10.^16 Most of these slaves
came from Mozambique, although about a quarter of them came from Kilwa.
Numerically, this slave trade to the Mascerene islands was not large, amounting
to about 6,000 per year at the most. Furthermore, it was hampered by the
Anglo-French rivalry, which led to the British taking the Ile de France (now
renamed Mauritius), a ban on slave importation in 1821, and a treaty with the
Sultan of Muscat in 1822 banning the export of slaves by Omanis to Christian
nations. But Bourbon (renamed Réunion) remained in French hands and con-
tinued to receive slaves from various East African ports—Zanzibar, Mombasa,
Takaungu and Lamu. Moreover, in the 1840s and 1850s the French obtained
slaves from Zanzibar under the so-called 'free labour' system, according to
which slaves had to sign a labour contract affirming that they were going
voluntarily before their Arab masters could be paid by French agents. Soon
'free labourers' were coming from Zanzibar, Kilwa and Mozambique in
large quantities.
In 1847, Seyyid Said, under strong pressure from the British, signed a
treaty banning the exports of slaves beyond his dominions in East Africa. But