Justinian's law code revised and adapted earlier written laws from

Ruman Jurists / Roman law

Explanation:

Justinian Law code was created in 529 CE. But, not all the content created by Justinian I himself. Justinian I formed a group of committees. This committee consisted of 10 men who were tasked to compile the Laws that implemented in Rome during 753 BC - 491 CE.

After the law was compiled, He added several additional Law as an adjustment to address both societal and economic issues that exist in Byzantine empire but never been experienced by the Roman empire.

i think it was   tsar alexander ii