When the Abyssinians came to the rescue of the Christians in Yemen in the 6th century:
Source: Gamaladdin A-Shami and his son Dr. Hashim A-Shami. (1997). AL-Manhal Fi Tarikh Wa Akhbar AL Afar (Al-Danakil), (The source on History and Narrative of the Afar (Al-Danakil. Cairo, Kamil Graphics., L:S:B:N. 977/19/4208/5, in 740 pagesThe account is detailed in Pages: 124 – 132
The book was translated to Amharic, with additions to the Arabic version in 2007 with the title (ዓፋር (ደንከል) ታሪክና መረጃ አርክ ምንጭ).