Smallest Codex Known from Antiquity Circa 450 CE The Cologne Codex Mani (Cologne Mani-Codex, Codex Manichaicus Coloniensis ) a vellum codex describing the life of Mani , the prophet and founder of Manichaeism . Written in Greek on leaves measuring 3.5 x 4.5 cm or 1.4 x 1.18 inches, it was originally