gems, archaeology, archaeogemology, Africa, East Africa, Tanzania, Kenya, early trade, Rome, Red Sea, Periplus

The Swahili coast has been linked to the ancient trading network of the early centuries A.D. The anonymous author of the Periplus Maris Erythraei (A.D. 40–70) and Ptolemy (A.D. 2nd–3rd century) called it Azania, and in the second half of the first millennium A.D. Arab geographers called it Zanj. The Periplus, a travel and commercial guide, provided information about centres of trade and goods exchanged along the Red Sea, in eastern Africa, and in India. The Romans had destroyed Aden, the port used by Arabs to control trade with India, and learned the secret of the monsoon winds (for conspectus see Cinimo 1994, Begley and de Puma 1991). Both the Periplus and Ptolemy report an Azanian emporium known as Rhapta as the last market to the south known in the Roman world. Ptolemy reported Rhapta as being a metropolis located at 8° S and slightly (1°) inland near a major river with a similar name (see Huntiford 1980, Casson 1989, Horton 1990).