303 AD
Emperor Diocletian launched the most devastating persecution of Christians in Roman history. Beginning in 303 AD, he issued a series of edicts that ordered the destruction of all Christian churches, the burning of all Scriptures, the stripping of Christians of civil rights, and the imprisonment of all clergy. Those who refused to sacrifice to the Roman gods were executed.
The persecution was so severe that it caused a crisis within the Church itself. Many Christians apostatized under pressure, handing over Scriptures or making sacrificial offerings to save their lives. After the persecution ended, the Church had to deal with the question of how to readmit these 'lapsed' Christiansβa controversy known as the Donatist schism in North Africa.
The persecution ultimately failed. Within a decade, Constantine would convert to Christianity and make it the favored religion of the Empire. The Martyrology of the Church preserves the names of thousands who died during this period. Key Sources: Lactantius, De Mortibus Persecutorum; Eusebius, Church History; CCC 759