Complex sentence: The original "Codex Justinianus" was promulgated in April of 529 by the C. "Summa," which made it the only source of imperial law, repealing all earlier codifications.
Split into simpler sentences: The original "Codex Justinianus" was promulgated in April of 529 by the C. "Summa". This made it the only source of imperial law, and repealed all earlier codifications.