It officially began at the Council of Nicaea in 325 AD by Emperor Constantine.
Yes, both the Edict of Milan in 313 AD and the Council of Nicaea in 325 AD occurred during the period of Roman Christianity. The Edict of Milan legalized Christianity in the Roman Empire under Emperor Constantine, while the Council of Nicaea was convened by Constantine to address theological disputes within the Christian community.
The Tiber is near Rome.
No, Nicaea, Bithynia is located in modern day Turkey, near the Bosporus. However, Bithynia has periodically passed under Greek political control since the 5th Century B.C.
Battle of Nicaea happened in 193.
Sporus of Nicaea was born in 240.
Sporus of Nicaea died in 300.
Empire of Nicaea ended in 1261.
Empire of Nicaea was created in 1204.
Mount Zion is near Jerusalem, which is a long way from Rome.
The Tiber not only begins near Rome, but flows through the city.
The Seljuk Turks used Nicaea as the capital of their Seljuk Empire beginning in 1081; in 1097, Nicaea fell back into Byzantine control. In 1204, after the Fourth Crusade, the Laskaris family made Nicaea the capital of their Empire of Nicaea. This empire lasted until 1261.