Cat. xi. 4, note 3.  See Newman’s notes on Athanasius, Contra Arian. Or. I. viii. 1; Ib. Or. III. xxv. 9; Ib. xxvii. 3.  Marcion’s doctrine of three first principles (τριῶν ἀρχῶν λόγος) is discussed by Epiphanius (Hæres. xlii. 6, 7).  See also Tertull. Contra Marcion. I. 15; Euseb. Hist. Eccles. V. 13.