Somali Red Sea trade network and their collusion with Arabs to prevent Indian-Roman contact in the first century (I've only posted a few tidbits, you can find more info in the link below):



https://books.google.com/books?id=u9w8A ... ia&f=false
Here's the full text of the Periplus and its description of the country of the "Berbers", as Somalis were commonly referred to.
http://legacy.fordham.edu/halsall/ancient/periplus.asp
The Omanis, Portuguese, Italians et al. of the Swahili coast were much later developments.