The empire did not contribute much to Roman religion. This religion was well established before Roman imperial expansion, including the Greek influence on it. This influence came right from the early days of Rome, centuries before she conquered mainland Greece. It came from the Greek colonies (settlements) the Greeks established in southern Italy and Sicily in the 8th century BC and early 7th century BC.
Christianity
Augustus continued the polytheistic religious observance observed within the Empire.
Through most of their history the ancient Romans had their own religion: Roman Religion. In the Later Empire Christianity spread in the Roman Empire, was endorsed by the Roman emperors and became state religion.
The dominant religion in the Roman Empire was the Roman religion until Christianity became the dominant religion.
It was mainly Christianity, as that was the official religion of the Roman Empire.
In the Roman Empire up to the time of Constantine, the official religion was Greco-Roman paganism. After Constantine it became Christianity.
Christianity was made the official religion of the Roman empire in 380 AD under emperor Theodosius I.Christianity was made the official religion of the Roman empire in 380 AD under emperor Theodosius I.Christianity was made the official religion of the Roman empire in 380 AD under emperor Theodosius I.Christianity was made the official religion of the Roman empire in 380 AD under emperor Theodosius I.Christianity was made the official religion of the Roman empire in 380 AD under emperor Theodosius I.Christianity was made the official religion of the Roman empire in 380 AD under emperor Theodosius I.Christianity was made the official religion of the Roman empire in 380 AD under emperor Theodosius I.Christianity was made the official religion of the Roman empire in 380 AD under emperor Theodosius I.Christianity was made the official religion of the Roman empire in 380 AD under emperor Theodosius I.
Roman Catholicism
By killing the queen bodica
The emperor Theodosius I declared Christianity to be the official religion of the Roman empire. In fact, he made Christianity mandatory for all.
Christianity
No religion made the Roman empire fall. The western empire fell because of internal and external pressures.