The Roman Empire had been divided by Diocletian, and that came in and out of practice (sometimes two empires, sometimes one), until the city of Rome itself was sacked and occupied by barbarians. Eastern emperor Justinian made an attempt to reconquer the lost provinces during the 6th century. The eastern empire, usually called Byzantine, didn't fall until after the sacking of Constantinople by the Turks in 1453.
The Justinian Code was issued around 530, but the article doesn’t say if this was a fragment of it.