The early church began in the 1st century AD after Jesus’ death, resurrection, and ascension, when the Holy Spirit empowered the apostles at Pentecost (Acts 2). The gospel spread rapidly through the Roman Empire despite persecution from Jewish authorities and Roman rulers. Leaders like Peter, Paul, and John established Christian communities, wrote letters (later part of the New Testament), and defended the faith against false teachings. By the 4th century, Christianity moved from being persecuted to becoming legally recognized under Emperor Constantine, setting the stage for organized church structures, councils, and the formation of creeds like the Nicene Creed.