Christianity originated in the Roman province of Judea as a sect within 1st-century Judaism.

Apostles, most notably Paul of Tarsus, were instrumental in spreading Christian teachings to non-Jewish (Gentile) communities.

The religion's promise of salvation and a personal relationship with God appealed to many across the empire, including the poor and women.

Early Christian communities faced sporadic and localized persecution from Roman authorities, who viewed them as disloyal for refusing to worship the emperor.

Major empire-wide persecutions occurred under emperors like Diocletian in the early 4th century.

Despite persecution, the religion continued to grow, aided by a network of organized communities led by bishops.

Emperor Constantine's conversion in the early 4th century was a major turning point for the religion's status.

The Edict of Milan in 313 CE, issued by Constantine, granted religious tolerance throughout the empire, effectively legalizing Christianity.

The Council of Nicaea in 325 CE was convened by Constantine to establish a uniform Christian doctrine.

In 380 CE, Emperor Theodosius I made Nicene Christianity the official state religion of the Roman Empire.