Final answer:
The Kingdom of Ethiopia, historically known as the Kingdom of Abyssinia, was the first African state with a Christian ruler and maintained its Christian faith despite the spread of Islam in surrounding regions.
Step-by-step explanation:
The Kingdom of Ethiopia was the first state in Africa with a Christian ruler. This region, known historically as the Kingdom of Abyssinia, was a successor state of Aksum and Zagwe and maintained Christianity despite Islam becoming the dominant religion in surrounding areas. Ethiopian rulers such as the legendary Christian king Prester John, a figure often mentioned in medieval European literature, exemplify the country's connection to early Christianity. The Kingdom of Ethiopia, with its enduring Christian faith, played a significant role in the mythos of European explorers, including the Portuguese who sought Prester John's kingdom in the 1440s.