The Byzantine Empire, the Greek eastern section of the old Roman Empire, survived the disintegration of the Latin West by approximately a thousand years. The phenomenon was due to political unity, larger population, and more wealth. A brief survey of this empire reveals its rise and gradual decline.
Justinian the Great was Byzantine Emperor from 527 AD to 565 AD. He was one of the most important figures from Classical Antiquity to the Middle Ages, a period of time referred to as Late Antiquity in Europe and the Mediterranean. During his reign, Justinian I sought to revive the Empire's greatness by reconquering the lost western half of the classical Roman Empire and the Gothic Wars, which took place between 535 AD and 568 AD, were motivated by that very cause. Justinian I was determined to recover provinces of the former Western Roman Empire, which had been lost to invading barbaric tribes in the previous century, the Migration Period. .
The Corpus Juris Civilis, otherwise known as the Body of Civil Law is the modern name for a collection of works in jurisprudence, issued from 529 to 535, by order of Justinian I, Eastern Roman Emperor. It is also referred to as the Code of Justinian; although his name belongs more appropriately to the part titled Codex. The work had three parts: the Code or Codex, which was a compilation of imperial enactments to date; the Digest or Pandects, an encyclopedia composed of mostly brief extracts from the writings of Roman jurists; and the Institutes or Institutiones, a student textbook, mainly introducing the Code or the Digest. All three parts, including the textbook were given the force of the law. They were intended to be used together as a sole source of the law. However, Justinian found himself having to enact further laws and today these are counted as the fourth part of the Corpus, the Novels or Novellae Constitutiones.
The Byzantine (East Roman) Emperors combined the power of the secular government with the religious power of the Church, known as Ceasaropapism, from the 330 AD consecration of Constantinople through the tenth Century.