I think you can lean a lot about a society by seeing how they perceived distant people with alien cultures. Also, the idea of an ancient person traveling vast distances and seeking to teach people about what he saw there really captures my heart and imagination. Can you recommend some other sources from antique authors writing about distant places they actually visited?
Have you heard of Cosmas Indicopleustes' Christian Topography? It seems to be known mostly for claiming the Earth is in fact flat (or at least Ark of the Covenant-shaped) but IIRC he also has some interesting descriptions of people/events at the southern end of the Red Sea.