Kingdom of Aksum

The Kingdom of Aksum ruled the Horn of Africa and parts of South Arabia from around the first century AD until its collapse under uncertain circumstances around 960, emerging from the earlier Dmt civilization and governed from the city of Axum, with Kubar serving as capital after about 800. At its peak around 525 AD the kingdom spanned roughly 2.5 million square kilometers across present-day Eritrea, northern Ethiopia, Djibouti, Sudan, Yemen and Saudi Arabia, and in the third century the Persian prophet Mani named it one of the four great powers of the world alongside Rome, Persia and China, reflecting its position astride the trade route between Rome and India; Aksum issued its own gold, silver and copper coinage. Initially polytheistic, the kingdom adopted Christianity as its state religion in the mid-fourth century under King Ezana. Its decline over its final three centuries, sometimes called a dark age, followed Persian and Muslim dominance of Red Sea trade, the loss of Roman trading partnerships, the expansion of Beja nomadic groups, and environmental pressures, before the kingdom's collapse around 960.