Pluperfect Active.—The pluperfect is formed by adding -εα, -εας, -εε, -ετον, -ετην, -εμεν, -ετε, -εσαν to the reduplicated stem. By contraction from ἐλελυκεα, -εας, -εε come the forms ἐλελύκη, -ης -ει (ν). In the later language ει spread from the 3 sing. and was used throughout, as ἐλελύκειν, -εις, -ει, -ειτον, -είτην, -ειμεν, -ειτε, and very late -εισαν. The best Mss. of Demosthenes have -ειν in 1 sing. Instead of the simple pluperfect we find periphrastic forms, 599 a.
Herbert Weir Smyth [n.d.], A Greek Grammar for Colleges; Machine readable text [info] [word count] [Smyth].