Abstract
The persecution begun by Diocletian and Galerius which lasted from 303 to 312 is known as the "Great Persecution.” During recent decades it has been the object of much research, but it still presents many problems, some of which perhaps will never be solved. The most important sources for this persecution are the writings of Eusebius and Lactantius, but a considerable amount of information can also be derived from the acts of the martyrs.|One of the most difficult problems connected with this persecution is that of determining the reasons for Diocletian’s change of policy from twenty years of tolerance to violent persecution. Many historians believe that this persecution was due to the influence of his co-regent Galerius, but others attribute it to his own policy of restoration. The violent anti-Christian polemics of writers such as Porphyry and Hiercles undoubtedly had a far reaching influence together with the deep seated hostility of the people toward foreign cults. In 297 Diocletian published an edict against the Manichees indicating that not only Christianity, but any religion considered dangerous to the empire and the established state religion might be outlawed.