The Law of Citations (Lex citationum) was a Roman law issued from Ravenna in AD 426 by the emperor Valentinian III, or rather by his regent mother, Galla Placidia Augusta, to the Senate and the people of Rome, and it was included in both Theodosius II's law compilation of 438 (Codex Theodosianus 1, 4, 3) and the first edition of the Codex Justinianus.