That the word began very early to be used in this new sense, is evident from Justin Martyr’s explanation of it in his First Apology, c. 61; where, after speaking of instruction in Christian doctrine, of the profession of faith, and the promise of repentance and holy living, as the necessary preparations for Baptism, he thus proceeds:  “And this washing is called Illumination (σωτισμός), because they who learn these things are illuminated in their understanding. ὡςφωτιζομένων τὴν διάνοιαν τῶν ταῦτα μανθανόντων.”  The same transition of the meaning from instruction to Baptism is clearly implied by Clement of Alexandria:  “Among the barbarian philosophers also to instruct and to enlighten is called to regenerate Strom. V. c. 2, § 15.,” and again:  “For this reason the teaching, which made manifest the hidden things, has been called illumination (φωτισμός) Strom. V. c. x. § 65.  Cf. V. c. viii. § 49..”