In which year did Theodosius declare Christianity the official religion of the Roman Empire?

In which year did Theodosius declare Christianity the official religion of the Roman Empire?

• A. AD 313
• B. AD 410
• C. AD 380
• D. AD 529

Answer: (C)

The main idea is when the Roman Empire first defined Christianity as its official faith. In 380 CE, Theodosius I, together with Gratian and Valentinian II, issued the Edict of Thessalonica. This decree made Nicene Christianity the empire’s official religion and required everyone to follow it, marking a formal establishment of Christianity as the state faith. Before this, Constantine’s Edict of Milan in 313 granted tolerance to Christians, but it did not declare Christianity the official religion. The other dates correspond to different moments and do not establish the empire’s official faith in the same way.

The main idea is when the Roman Empire first defined Christianity as its official faith. In 380 CE, Theodosius I, together with Gratian and Valentinian II, issued the Edict of Thessalonica. This decree made Nicene Christianity the empire’s official religion and required everyone to follow it, marking a formal establishment of Christianity as the state faith. Before this, Constantine’s Edict of Milan in 313 granted tolerance to Christians, but it did not declare Christianity the official religion. The other dates correspond to different moments and do not establish the empire’s official faith in the same way.