Christianity became the official state religion of the Roman Empire under the 4th century Roman Emperor Constantine, mainly for political reasons. From this union of state and religion sprung what is known of today as Roman Catholicism.
Depends on what you consider Christianity.
"Catholicism" was decreed as a national religion of the Roman Empire on February 27, 380 with the Edict of Thessalonica. Unfortunately too many pagans were involved in this venture so the result was a corrupt version of the beautiful, loving doctrines brought to us by the Messiah. EX: Christ taught to turn the other cheek, love your enemies and treat everyone with respect. It was the Catholic policy to send men out to kill heretics. Several Popes sent Crusaders out to kill Muslims; Russian Catholics established hated pogroms against the Jews; The Inquisitions burned people alive who disagreed with the Catholic doctrines. Hardly acts of decent Christians.
To answer your question: Never.
A basic timeline:
Before AD 313 - Christianity is illegal and Christians are persecuted.
AD 313 - Constantine, the first Christian emperor, issues the "Edict of Milan" establishing a policy of religious tolerance.
AD 380 - Emperor Theodosius I makes Christianity the official religion of the Roman Empire.
** (these answers are all from wikipedia, not guaranteed to be accurate)
313 a.D.....actually in 313 a.d. The emperor Constantine issued the edict of Milan which simply granted religious freedom to the Christians allowing the to practice their religion without fear of persecution.however it wasn't until 395 a.d. That the emperor theodocious officially adopted christianity as the religion of Rome.
Emperor Theodosius declared Christianity the state religion in 381, and then banned the public worship of the pagan gods although probably more than half the population were still pagans.
Never,If he had truly been converted he and the council of niecea would have never changed the sabbath to SUNday or incoperated all their pagan holiday worship system
I am like catholic so i dont really know for sure and stuff, but i learned st peter got some empiors to convert which made other empiors covert!
Late 4th Century CE , decreed by Emperor Theodosius.
The Roman empire became Christian by law. Theodosius I, in 380, ordered Christianity for all.
Constantine I, Emperor of Rome in the beginning of the 4th century.
Christianity was established as the main religion of Rome in AD 313.
Christianity
It was Christianity
the Romans religion was Christianity
The major religion in India is Hinduism, while in Rome is Christianity
christianity
Christianity
Rome's official religion was Christianity after 380 AD. Before this time there was no "official" religion as Rome was tolerant of all beliefs.
The emperor who made Christianity Rome's official religion was Theodosius I.
Christianity
"Christianity" has never been a language. It has always been a religion.