Subjected to more criticism than any other book now incorporated in the New Testament, the Apocalypse--popularly accredited to St. John the Divine--is by far the most important but least understood of the Gnostic Christian writings. Though Justin Martyr declared the Book of Revelation to have been written by "John, one of Christ's apostles," its authorship was disputed as early as the second century after Christ. In the third century these contentions became acute and even Dionysius of Alexandria and Eusebius attacked the Johannine theory, declaring that both the Book of Revelation and the Gospel according to St. John were written by one Cerinthus, who borrowed the name of the great apostle the better to foist his own doctrines upon the Christians. Later Jerome questioned the authorship of the Apocalypse and during the Reformation his objections were revived by Luther and Erasmus. The once generally accepted notion that the Book of Revelation was the actual record of a "mystical experience" occurring to St. John while that seer was an exile in the Isle of Parmos is now regarded with disfavor by more critical scholars. Other explanations have therefore been advanced to account for the symbolism permeating the volume and the original motive for its writing.