The history books tell of a kingdom in central Ethiopia, in the region around the modern capital, Addis Abbaba, named Shoa (or Shewa). It was Muslim, in contrast to the Christian religion of the neighboring Zagwe Dynasty ruling Axum. Shoa existed possibly as early as the 9th century AD, and was absorbed by a neighboring state in the 13th century. Until recently, there was little evidence of its existence. Now, archaeologists have announced that they have found the remains of three towns, including well-preserved mosques and cemeteries, in the area, which they believe date to this murky period.
I know virtually nothing about the archaeology of this part of the world, but find it fascinating that so much remains to be discovered.