Justinian I (aka the Great) was an emperor of Rome and ruled 627-565. What he did was fundamental to the state of Roman law as we know it. He started off by wanting to rebuild the old Emporium Romanum and in order to do so, he had to clean up the mess that become of the “legal system” in ancient Rome. It is through this that he established his position as an emperor, and also stabilised the social system (esp. the position of slaves in society). He carried out the bulk of his “cleaning up” within 7 years, the rest was left for minor allterations. The Code itself (Codex Iustinianus) was what he began with and it dates back to 529 a.c. It’s a collection of Constitutions (leges) And if you think about it – by “cleaning up” AND regulating the law governing ancient Rome it mirrors the state of society and especially the situation of the slavery (f.e. it gave certain priviledges to slaves, f.e. they were allowed limited ownership rights etc.). It’s such a complex piece of work it cannot be defined in a couple of short sentences – in general, it bridged a gap between what was considered “folk” law and an established legal system. It’s a profound attempt to lay down ground rules in a vast, highly differenciated society.

Hope that helps.