Final answer:
Christianity reached the kingdom of Aksum primarily through the work of a Syrian teacher, Frumentius, who converted King Ezana and later founded Ethiopia's first Christian monastery as Bishop Selama. The trade that the Aksumite Kingdom engaged in with the Arabian Peninsula allowed for cultural exchanges, but it was not the primary mode of spreading Christianity there.
Step-by-step explanation:
The initial spread of Christianity to the kingdom of Aksum was through the efforts of a Syrian teacher named Frumentius. Shipwrecked on the Eritrean coast, Frumentius was brought to the royal court and later converted King Ezana, who was a polytheist at the time. After his baptism, Ezana sent Frumentius to Alexandria, where he was appointed as the bishop for Ethiopia by Bishop Athanasius. Consequently, Bishop Selama, as Frumentius became known, founded Ethiopia's first Christian monastery, establishing the roots of Christianity in Aksum.
The Aksumite Kingdom was heavily involved in trade with the Arabian Peninsula and beyond, which also facilitated cultural exchanges, but the introduction of Christianity was not through trade or other methods like conquest or diplomatic treaties. Instead, it was the individual influence of Frumentius and later missionaries who extended the Christian faith throughout the countryside by establishing monasteries and blending local beliefs into church ceremonies and holidays.
Aksum's connection to Christianity is also evident in its artifacts and monuments, such as coins bearing the symbol of the cross, which appeared after the king's conversion to Christianity. The Aksumite and Himyarite leaders expressed their religious devotion publicly by creating inscriptions and building monuments to their faith.