Final answer:
Zere-yaqob made significant contributions to Ethiopian Christianity by resolving theological debates, participating in church gatherings, and spreading the faith through the establishment of monasteries.
Step-by-step explanation:
Zere-yaqob, also known as Zar'a Ya'eqob, made significant contributions to Ethiopian Christianity during his reign as emperor from 1434 to 1468. He resolved a theological debate over the observance of the Sabbath that had been ongoing for over a century. He also sent a delegation to the Council of Florence in 1441 to join the church gathering. Additionally, he played a role in the conversion of the Ethiopian Church to Christianity and established monasteries and hermitages to spread the faith.