Justinian's law reforms are those changes made by the Byzantine emperor Justinian I.
Some of these reforms include making the sale of zonal governorships illegal, building new worship centres and overall regulating practice of religion.
The Emperor totally made amendments to the entire Roman law and these reforms are called Corpus juris civilis
Justinian also restructured the way the government was run and these reforms were bold ones because nobody else had dared to do them.
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