O death, where is thy sting? O grave, where is thy victory?
The book of Enoch was written in the 2nd century B.C., and was popular for about 500 years, with both Jews and early Christians. It is one of 15 works of the Jewish apocrypha, and the Jews rejected the book of Enoch when they made a canon of their own scriptures late in the second century A.D.
During the first three hundred years of Christianity, early church leaders made reference to it. The early second century "Epistle of Barnabus" makes much use of the Book of Enoch. Second and Third Century leaders, including Justin Martyr, Irenaeus, Origin and Clement of Alexandria all reference it. Tertullian (160-230 A.D.) even called the Book of Enoch "Holy Scripture". The Ethiopic Church even added the Book of Enoch to its official canon. It was widely known and read the first three centuries after Christ. This and many other books became discredited after the Council of Laodicea. And being under ban of the authorities, afterwards it gradually passed out of circulation.
Later theologians disliked it because of its content regarding the nature and actions of fallen angels. The Reformers, influenced by the Jewish canon of Old Testament, also considered it as non-canonical and thus it was removed from the Protestant Bible. Catholics apparently do consider the book of Enoch as canonical, as one of 12 of the 15 they accept.
Many of the early church fathers also supported the Enochian writings. Justin Martyr ascribed all evil to demons whom he alleged to be the offspring of the angels who fell through lust for women (from the Ibid.)--directly referencing the Enochian writings.
Athenagoras, writing in his work called Legatio in about 170 A.D., regards Enoch as a true prophet. He describes the angels which "violated both their own nature and their office." In his writings, he goes into detail about the nature of fallen angels and the cause of their fall, which comes directly from the Enochian writings.
Many other church fathers: Tatian (110-172); Irenaeus, Bishop of Lyons (115-185); Clement of Alexandria (150-220); Tertullian (160-230); Origen (186-255); Lactantius (260-330); in addition to: Methodius of Philippi, Minucius Felix, Commodianus, and Ambrose of Milanalso--also approved of and supported the Enochian writings.
The twentieth-century discovery of several Aramaic Enochian texts among the Dead Sea Scrolls prompted Catholic scholar J.T. Milik to compile a complete history of the Enochian writings, including translations of the Aramaic manuscripts.
The book of Enoch, documentary made by History Channel.