The most recognized emperor of the Byzantine Empire, Justinian the Great (453-565), is still studied today as a philosopher of law. He was born in Tauresium, Illyria to a peasant stock family. At a young age Justinian's uncle, Emperor Justin I, adopted him and in 527 made him the co-ruler of the empire. Following his death 4 months after Justinian became the sole emperor of the Byzantine Empire. Justinian is primarily known today for his reform and codification of Roman law. During his rule he noticed that the laws were confusing and so he gathered together 1000 years of Roman law into one code, The Justinian Code. This code consisted of 4 books; the Codex Constitutionum, a collection of decrees of the emperors; the Digest interpreted and updated past legal decisions; the Institutes, stated legal principles in simple terms; and the Novels which included decrees of Justinian after codification ("Justinian I,"). These 4 books together made up the Code of Justinian, Civil Law and Natural Law. The code emphasized equality and that all laws applied to everyone regardless of their status and wealth in society. The Justinian Code became the basis for western law and the legal philosophy behind it functioned as the pillars of the Napoleonic Code.
Thomas Aquinas "the angelic doctor", a wealthy, well-educated philosopher, preacher and theologian, was born in Lombardy, Italy in circa 1225. He was born to a royal family in southern Italy. During his university years he was attracted to the life of a monk and when he joined a religious order his parents took him under captive and locked him up in the castle tower in hopes of changing his mind. A year later he escaped and ordained his life as a priest. Thomas Aquinas practised four types of law; eternal law which states that the laws of the universe is governed by God eternally; divine law as God's revealed words ; natural law is eternal law but to humans which we know by reason; and human law which was created by humans to fulfil natural law. He did not assume that laws cause people to be good, but rather "man obeys a law due to him being good". He believed that the existence of God can only be proved in 5 ways. He also believed that good is to be done and pursued, evil is to be avoided, preserve life and ward off its obstacles, reproduce and raise offsprings, pursue knowledge and live together in society and finally that natural law cannot be applied to everyone in the same way. Thomas Aquinas ranked as one of the most influential thinkers of medieval scholasticism. He combined theological principles of faith with the philosophical principles of reason. He had two major works Summa Contra Gentiles ("Summary of Arguments against the Disbelievers) and Summa Theologica which forms the "classical systematization of Roman Catholic theology". In 1274, Thomas Aquinas was in his death bed and he uttered his last words to the Cistercian monks: "This is my rest forever and ever: here will I dwell for I have chosen it." (Psalm 131:14).