In Cat. x. § 14 Cyril reminds his hearers that he had preached on the words after the order of Melchizedek at the public Service on the Lord’s day.  As he does not here employ his usual phrase “yesterday,” we may infer that Cat. x. was delivered not earlier than the Tuesday following the 4th Sunday in Lent, the Epistle for that Sunday in the Eastern Church being Heb. vi. 13–20, which ends with the words on which Cyril had preached.  The next two Lectures followed Cat. x. immediately on successive days, Wednesday and Thursday, the word “yesterday” recurring in xi. § 1, and xii. § 4.