Which of the following continuities in the development of African states in the period circa 1200-1450 most likely explains the prevalence of Christianity in Ethiopia

Historians have recently discovered a historical journal published in the early twentieth century. the journal contains facts based on original sources about the downfall of the early byzantium empire. historians consider this long-lost journal to be a breakthrough in their understanding of the byzantium empire. based on this information, the journal is a source.