The "Panarion" furnishes very valuable information concerning the religious history of the fourth century, either because the author confines himself to transcribing documents preserved by him alone, or because he writes down his personal observations. With regard to Hieracas ("Haer.", lxvii), he makes known a curious Egyptian sect by whom asceticism and intellectual work were equally esteemed. In connection with the Melitians of Egypt ("Haer.", lxviii), he has preserved important fragments of contemporary Egyptian history of this movement. With regard to Arianism ("Haer.", lxix), he provides an apocryphal letter of Constantine. He transcribes two letters of Arius. He is the only one to give us any information concerning the Gothic sect of the Audians ("Haer.", lxx), as well as the Arabian sect of the Collyridians. He has made use of the lost report of the discussion between Photinus ("Haer.", lxxi), and Basil of Ancyra. He has transcribed a very important letter from Bishop Marcellus of Ancyra ("Haer.", lxxii) to Pope Julius, and fragments of the treatise of Acacius of Caesarea against Marcellus. With regard to the Semiarians ("Haer.", lxxiii), he gives in the Acts of the Council of Ancyra (358) a letter from Basil of Ancyra and one from George of Laodicea, and the stenographic text of a singular sermon of Melitius at the time of his installation at Antioch. In the chapter dealing with the Anomeans ("Haer.", lxxvi) he has preserved a monograph of Aetius.