The Great Persecution under Diocletian and his imperial colleagues and successors is a foremost concern of modern scholarship on Roman persecution of Christians. This book is a systematic and comprehensive study of that persecution. Its focus is on events from 284 when Diocletian became emperor, to 313, when full religious liberty was granted to all religions by the so-called Edict of Milan. At least nine imperial orders were issued in 303 to 312 against Christianity. While Diocletian's orders were more concerned with the privileged upper classes of Christians, Maximinus Daia's orders were aimed at isolating all Christians from the Roman community. The enforcement of the imperial orders, and the sufferings of Christians under them, are examined on a diocese-by-diocese basis, comparing the situation in the West and in the East. In the late fourth century, Prudentius of Calahorra, poet and imperial official, complained about the loss of records on local martyrs, exclaiming, 'Alas for what is forgotten and lost to knowledge in the silence of the olden time! We are denied the facts about these matters, the very tradition is destroyed.' This book draws together the remains of what Prudentius feared was forgotten for ever.