Constitution of The Late Roman Empire

The Constitution of the Late Roman Empire was an unwritten set of guidelines and principles passed down mainly through precedent. The constitution of the Roman Principate (the early Roman Empire), which was established by the emperor Augustus in the 1st century BC, had governed the "Roman Empire" for three centuries. Diocletian became emperor in 284, and his reign marked the end of the Principate and the beginning of the "Dominate" (from Latin dominus: "Lord" or "Master"). The constitution of the Dominate ultimately recognized monarchy as the true source of power, and thus ended the fiction of shared power between the "Roman Emperor" and the "Roman Senate".

After Diocletian had reorganized the superstructure of the constitution, he then reorganized the administrative apparatus of the government. When Diocletian abdicated the throne in 305, the Empire quickly descended back into chaos. After the chaos had subsided, however, much of Diocletian's constitution remained in effect. His division of the Empire into west and east, with each half under the command of a separate emperor, remained with brief interruptions of political unity. The capital of the Western Empire was never returned to Rome, the Senate and executive magistrates continued to function as Diocletian's constitution had originally specified, and Diocletian's civil and military divisions of the empire remained in effect. Later emperors, especially Constantine the Great, modified Diocletian's constitution, but it ultimately survived until the reforms of Justinian after the fall of the Western Roman Empire in 476.