Answer:
a) Emperor Constantine’s conversion to Christianity
Step-by-step explanation:
Flavio Valerio Aurelio Constantino was Emperor of the Romans from his proclamation by his troops on July 25, 306, and ruled a Roman Empire in constant growth until his death. He is also known as Constantine I, Constantine the Great or, in the Orthodox Church, the Eastern Orthodox Churches and the Greek Byzantine Catholic Church, like Saint Constantine.
Legalizer of the Christian religion by the Edict of Milan in 313, Constantine is also known for having refounded the city of Byzantium (now Istanbul, in Turkey), calling it "New Rome" or Constantinople (Constantini-polis, the city of Constantine). He convened the First Council of Nicaea in 325, which gave legitimacy to Christianity in the Roman Empire for the first time. It is considered that this was essential for the expansion of this religion, and historians, from Lactantius and Eusebius of Caesarea to our days, present him as the first Christian emperor, although he was baptized when he was already on his deathbed, after a long catechumenate.