This work aims at examining in a new light the reign of Theodosius II, for a long time neglected by the historiography. In particular, the legislation of the emperor, contained in his Codex Theodosianus, appears to be extremely worthy to be studied. In this code, the legislation specifically attributed to Theodosius seems to have, most of times, the function of confirming, precising or correcting the meaning and importance of measures of previous emperors, with the scope of impressing the sign of the Theodosian politics. This confers importance to that legislation which seems to reveal the new times, frequently presenting very original features. The study should be considered only the initial phase of an overall research on the legislation of Theodosius II.