Christianity was endorsed by the emperors during the Later Roman Empire. Mainstream Christianity was made sate religion and the sole legitimate religion in the Edict of Thesalonicca issued by the co-emperors Gratian and Theodosius I in 380. The purpose of the edict was to ban dissident Christian doctrines which were branded as heretic. Theodosius I persecuted the dissident doctrines. He also persecuted Paganism.During his reign pagan monuments, shrines and temples were destroyed. In areas of the empire pagans were executed if they did not convert to Christianity.
I would say religion was the ancient Romans' most significant contribution to Europe. Christianity developed from a religion among a small group of Jews (who lived in Judea, which was part of the Roman Empire) into a mass religion in the Roman days. It spread around the Roman Empire. It became state religion. Catholic Christianity and Orthodox Christianity developed during the Later Roman Empire. They were originally called Latin or Western Christianity and Greek or Eastern Christianity respectively. The former was the main form of Christianity in the western part of the Roman Empire and the latter was the main form of Christianity in the eastern part of the Roman Empire.
Christianity originated in the 1st century CE within the Jewish community in Judea, rooted in the teachings of Jesus of Nazareth, who was seen as the Messiah by his followers. As it spread throughout the Roman Empire, Christianity’s emphasis on monotheism and the belief in a single, personal God challenged the polytheistic traditions of Roman religion. This shift contributed to the gradual decline of pagan practices and the eventual establishment of Christianity as a dominant faith, influencing the development of monotheism in the empire and leading to significant theological and cultural transformations. The Edict of Milan in 313 CE further solidified Christianity's status, paving the way for it to become the official religion of the Roman Empire.
There was only one Roman Empire. Moreover, the Roman Empire did not study Christianity. An empire cannot study. The Roman Empire was where Christianity spread from Judea (which was a part of the Roman province of Syria). Both Catholic and Orthodox Christianity developed in the Roman Empire. Originally the were called Latin or Western Christianity and Greek or Eastern Christianity respectively. The former was the dominant form of Christianity in the western part of the Roman Empire and the latter was the dominant form of Christianity in the eastern part of this empire. There were also dissident Christian doctrines and sects.
Roman empire.
The emperor Theodosius I declared Christianity to be the official religion of the Roman empire. In fact, he made Christianity mandatory for all.
After the Emperor Constantine converted to Christianity, that became the official religion of the Roman Empire.
The Roman Empire made Christianity the official religion of the Empire, and 'encouraged' the peoples it conquered to convert.
If you mean "Christianity as an organized religion", it owes it growth and prominence to the present day mostly to the Roman Emperor Constantine, who on his accession in 324 AD made Christianity the Roman Empire's state religion.
I think when the Roman Empire went from a pagan state to adopting Christianity as its official religion was a significant event.
the religon that originated in the roman empire is Christianity
Christianity did not easily spread through the Roman Empire. See the related question, "How did Christianity spread throughout the Roman Empire?"
Christianity developed from a religion among a small group of Jews (who lived in Judea, which was part of the Roman Empire) into a mass religion in the Roman days. It spread around the Roman Empire. It became state religion. Catholic Christianity and Orthodox Christianity developed during the Later Roman Empire. They were originally called Latin or Western Christianity and Greek or Eastern Christianity respectively. The former was the main form of Christianity in the western part of the Roman Empire and the latter was the main form of Christianity in the eastern part of the Roman Empire.