The Codex Justinianus is a collection of laws and legal interpretations compiled under the direction of the Byzantine Emperor Justinian I in the 6th century. It is part of a larger legal reform known as the Corpus Juris Civilis, which aimed to consolidate and simplify Roman law for better governance and legal clarity. This codex served as a foundational text for legal systems in many European countries and influenced the development of modern law. It includes imperial constitutions and legal principles, reflecting the legal traditions of the Roman Empire and the evolving needs of Byzantine society.