This flight of early Muslims to Ethiopia is regarded as the First Hijra in Islamic history. The gratitude towards the Ethiopians is preserved in a Hadith:
"utruk al-habasha ma tarkukum"
Leave the Abyssinians alone, so long as they do not take the offensive!
Furthermore the Islamic tradition sees the Ethiopian ruler as having become a Muslim called Ahmed Najashi.
Archaeological findings from northeastern Shewa show that the first Muslim communities in that area must have been established as early as the 9th century.