Stone buildings among coastal settlements seem to have first been concentrated in the area north of the Tana Delta, an area which has been referred to as Swahilini. However, before the third/ninth century, the majority of the buildings in many of the settlements were, as already pointed out, mud and wattle houses. The roofs were of thatch, as are those found today, either of the fronds of the mwaa palm or of the makuti (bound leaves of the coconut tree). Even in subsequent periods such houses were still built, as they still are in present-day coastal towns. Short lengths of stone-built walls have been found but it is not certain whether they were part of larger structures.
As far as the origin of the coastal stone architecture is concerned, many historians have attributed it to Persia and Arabia. However, this diffusionist view is eschewed here in favour of more acceptable explanations.
– The material culture of the Swahili has no analogues in Arabia or Persia. The Swahili stone architecture has no detailed parallels to justify the conclusion that it originated in the Near East, Arabia or Persia. Instead it developed locally out of the mud and wattle
architecture prominent along the coast as a result of increasing economic wealth and socio-economic differentiation. The coastal architecture which has been so much used as a proof that the coastal urban centres were founded by Arabs uses no materials which are not locally obtainable. Coral and coralline limestone which dominated the buildings were locally quarried. The mortar and plaster were also made from the available coral and gypsum. –
Nowhere in the Near East are there sufficiently numerous or detailed parallels to enable clear conclusions on Persian or Arabic origin to be made. All the raw materials (coralline, limestone, coral, mortar, plaster) have always been found locally in plenty and there is nothing to prevent an innovative architectural element developing locally. However, some influence from traders and other immigrants cannot be ruled out.
F. T . Masao (Tanzania); archaeologist; specialist in the Later Stone Age and Prehistory rock art; author of numerous works on the subject; Director, the National Museums of Tanzania.
H . W . Mutoro (Kenya); specialist in African archaeology; author of numerous works on the subject.
Source: General History of Africa Vol.III. [Editor: M. El Fasi, Assistant Editor: I. Hrbek] Africa from the Seventh to the Eleventh Century. Chapter 21. The East African coast and the Comoro Islands.