Kingdom of Aksum

Founded in the 1st. century when a single king replaced a confederation of chiefdoms and forged a united kingdom that would dominate for the next 6 centuries located in what is now Eritrea. Aksum had a major role in the trade route between the Roman Empire and Ancient India, Aksum rulers created their own Askumite currency. They traded ivory, tortoise shell, gold and emeralds.Importing silk and spices,Aksums access to both the Red Sea and Upper Nile enabled them to profit in trade from African, Arabian, Indian states

Wikipedia says Aksum adopted Christianity in the 7th century.However further in the article it says it was adopted by Askumites in 325 or 328 AD under King Ezana. The kingdoms capital also called Axum is now a town in Tigray Rregion.They say its the resting place of The Ark of Covenant

Aksum was previously thought to have been founded by the Sabaeans who spoke a language from the Semitic branch of the Afroasiatic language family. Evidence suggests that Semitic-speaking Aksumites semiticized the Agaw people, who originally spoke other Afroasiatic languages from the family's Cushitic branch

Aksum remained a strong and powerful trading power until the rise of Islam in the 7th century after its second golden age in the 6th century it began to decline ceasing the production of coins and the population being forced inland.