According to this law:
"The Manichaeans and the Phrygians, who are called Pepyzites, or Priscillianists, and likewise, the Arians, Macedonians, and Eunomians, the Novatians, the Sabbatians, and all other heretics must know that all privileges which are forbidden to them will continue to be denied.
If any one tries to contravene this, they will be punished" [CTh 16.5.59]
There is a long series of Roman imperial laws punishing heretics and anyone who diverges from what has become "orthodox" Christianity. Reiterating this separation from "true," orthodox Christianity and "heretical" Christianity indicates that the previous edicts designed to maintain the purity of Christianity haven't been upheld very well.