The genuineness of the four Gospels rests upon better authority than that of any other ancient writings. It is the general conclusion of the most eminent scholars that all four were written during the latter half of the first century. Before the end of the second century they were in general use and acceptance as one collection. They are mentioned by Tertullian, in a book written about A. D. 208, as being the work of two apostles and two disciples of apostles. Marcion also mentions their apostolic origin. Origen (who lived A. D. 185-253) refers to them as "the four elements of the church's faith." Theophilus, Bishop of Antioch (A. D. 168), also mentions the Gospels in his writings, and Jerome tells us that Theophilus arranged the four into one work. Tatian (who died about A. D. 170) compiled a Harmony of the Gospels. Justin Martyr (A.D. 99-165) gives many quotations from the Gospels. Many other witnesses might be cited to the same purpose. None of the original manuscripts are now in existence.