Romulus Augustulus in the context of "Barbarian"

The history of the Roman Empire covers the history of ancient Rome from the traditional end of the Roman Republic in 27 BC until the abdication of Romulus Augustulus in AD 476 in the West, and the Fall of Constantinople in the East in 1453. Ancient Rome became a territorial empire while still a republic but was then ruled by emperors, beginning with Octavian Augustus, the final victor of the republican civil wars.

Rome had begun expanding shortly after the founding of the Republic in the 6th century BC, though it did not expand outside the Italian Peninsula until the 3rd century BC, during the Punic Wars, after which the Republic expanded across the Mediterranean. Civil war engulfed Rome in the mid-1st century BC, first between Julius Caesar and Pompey, and finally between Octavian (Caesar's grand-nephew) and Mark Antony. Antony was defeated at the Battle of Actium in 31 BC, leading to the annexation of Egypt. In 27 BC, the Senate gave Octavian the titles of Augustus ("venerated") and Princeps ("foremost"), thus beginning the Principate, the first epoch of Roman imperial history. Augustus' name was inherited by his successors, as well as his title of Imperator ("commander"), from which the term "emperor" is derived. Early emperors avoided any association with the ancient kings of Rome, instead presenting themselves as leaders of the Republic.

The causes and mechanisms of the fall of the Western Roman Empire are a historical theme that was introduced by historian Edward Gibbon in his 1776 book The History of the Decline and Fall of the Roman Empire. Though Gibbon was not the first to speculate on why the empire collapsed, he was the first to give a well-researched and well-referenced account of the event, and started an ongoing historiographical discussion about what caused the fall of the Western Roman Empire. The traditional date for the end of the Western Roman Empire is 476 when the last Western Roman Emperor was deposed. Many theories of causality have been explored. In 1984, Alexander Demandt enumerated 210 different theories on why Rome fell, and new theories have since emerged. Gibbon himself explored ideas of internal decline (civil wars, the disintegration of political, economic, military, and other social institutions) and of attacks from outside the empire.

Many historians have postulated reasons for the collapse of the Western Roman Empire. Their conclusions usually belong in two broad schools: (1) external factors, such as military threats and barbarian invasions or (2) internal factors, such as a decline in "civic virtue" and military and economic capability. Most historians believe that the fall was due to a combination of both internal and external factors, but come down more heavily on one or the other as the most important cause of the fall. Modern scholarship has introduced additional factors such as climate change, epidemic diseases, and environmental degradation as important reasons for the decline. Some historians have postulated that the Roman Empire did not fall at all, but that the "decline" was instead a gradual, albeit often violent, transformation into the societies of the Middle Ages.

Odoacer (c. 433 – 15 March 493 AD), also spelled Odovacer or Odovacar, was a barbarian soldier and statesman from the Middle Danube who was an officer of the Roman army and deposed the Western Roman child emperor Romulus Augustulus to become the ruler of Italy (476–493). Odoacer's overthrow of Romulus Augustulus is traditionally understood as marking the end of the Western Roman Empire.

Although he ruled Italy, Odoacer styled himself a client of the Eastern emperor Zeno in Constantinople. He was addressed not only as Latin: rex but also as dux and patrician, the latter title granted by Zeno. In the sole surviving document from his chancery—and by the consul Basilius—Odoacer used the title of king. Backed by the Roman Senate, he distributed land with little resistance. Soldier unrest in 477–478 caused violence, but his later reign was stable. Though an Arian, he seldom interfered in the Trinitarian state church.

Zeno (/ˈziːnoʊ/; Ancient Greek: Ζήνων, romanized: Zénōn; c. 425 – 9 April 491) was Eastern Roman emperor from 474 to 475 and again from 476 to 491. His reign was plagued by domestic revolts and religious dissension, but was more successful on the foreign front. He is credited with further stabilizing the Eastern empire, while the Western Roman Empire fell following the deposition of Romulus Augustulus.

Born in Isauria, Zeno was known as Tarasis before adopting his Greek name and becoming an ally of Emperor Leo I, who saw the Isaurian general as an important counterweight against the Germanic leader Aspar. In 466, he married Leo I's daughter, Ariadne, with whom he had a son, Leo. On the death of Leo I in 474, Zeno's seven-year-old son took the throne as Leo II, with Zeno made co-emperor shortly after. Leo II died of an illness later that year, leaving Zeno as the sole emperor.

Anicius Manlius Severinus Boethius, commonly known simply as Boethius (/boʊˈiːθiəs/; Latin: Boetius; c. 480–524 AD), was a Roman senator, consul, magister officiorum, polymath, historian, and philosopher of the Early Middle Ages. He was a central figure in the translation of the Greek classics into Latin, a precursor to the Scholastic movement, and, along with Cassiodorus, one of the two leading Christian scholars of the 6th century. The local cult of Boethius in the Diocese of Pavia was sanctioned by the Sacred Congregation of Rites in 1883, confirming the diocese's custom of honouring him on the 23 October.

Boethius was born in Rome a few years after the forced abdication of the last Western Roman emperor, Romulus Augustulus. A member of the Anicii family, he was orphaned following the family's sudden decline and was raised by Quintus Aurelius Memmius Symmachus, a later consul. After mastering both Latin and Greek in his youth, Boethius rose to prominence as a statesman during the Ostrogothic Kingdom, becoming a senator by age 25, a consul by age 33, and later chosen as a personal advisor to Theodoric the Great.

The Ostrogothic Kingdom, officially the Kingdom of Italy (Latin: Regnum Italiae), was a barbarian kingdom established by the Germanic Ostrogoths that controlled Italy and neighbouring areas between 493 and 553. Led by Theodoric the Great, the Ostrogoths killed Odoacer, a Germanic soldier and erstwhile leader of the foederati. Odoacer had previously become the de facto ruler of Italy following his deposition of Romulus Augustulus, the final emperor of the Western Roman Empire, in 476. Under Theodoric, the Ostrogothic kingdom reached its zenith, stretching from Southern France in the west to Western Serbia in the southeast. Most of the social institutions of the late Western Roman Empire were preserved during his rule. Theodoric called himself "King of the Goths and Romans" (Latin: Gothorum Romanorumque Rex), demonstrating his desire to be a leader for both peoples.

Under Justinian I, the Byzantine Empire embarked on a campaign to reconquer Italy in 535. Witiges, who was the Ostrogothic ruler at that time, could not defend the kingdom successfully and was finally captured when the capital Ravenna fell. The Ostrogoths rallied around a new leader, Totila, and largely managed to reverse the conquest, but were eventually defeated. The last king of the Ostrogothic Kingdom was Teia.

Julius Nepos (died 9 May 480), or simply Nepos, ruled as Roman emperor of the West from 24 June 474 to 28 August 475. After losing power in Italy, Nepos retreated to his home province of Dalmatia, from which he continued to claim the western imperial title, with recognition from the Eastern Roman Empire, until he was murdered in 480. Though Nepos' successor in Italy, Romulus Augustulus (r. 475–476), is traditionally deemed the last western Roman emperor, Nepos is regarded by some historians as the true last emperor of the west, being the last widely recognised holder of the position.

A native of Dalmatia, Nepos began his career as the semi-autonomous governor of the province, succeeding his uncle Marcellinus, a prominent general, as magister militum ('master of troops') of Dalmatia. After the death of the western emperor Anthemius (r. 467–472), who had been appointed by the eastern emperor Leo I (r. 457–474), as well as Anthemius' successor Olybrius (r. 472), Leo sought to assert his authority in the west, granting Nepos command of an army in December 473 to attack Italy and depose Glycerius (r. 473–474), who had been proclaimed emperor by the Burgundian general Gundobad. Nepos left for Italy in the spring of 474, backed by Leo's successor Zeno, and landed with his army at Portus, near Rome. Nepos swiftly deposed Glycerius and was crowned western emperor in Rome on 24 June 474. He was the last emperor to be crowned in the city until Charlemagne in the ninth century. Whether the original intention of the invasion was to install Nepos as western emperor is unclear, but in any event, he was quickly recognised as the legitimate western emperor by Zeno.

Orestes (died 28 August 476) was a Roman general and politician of Pannonian ancestry. He joined the court of Attila the Hun in his native Pannonia, in which he reached a high position, becoming one of Attila's most trusted men. Orestes also held considerable influence in the late Western Roman Empire. His son Romulus Augustulus became Roman Emperor of the West.

The Kingdom of Odoacer, officially known as the Kingdom of Italy (Latin: Regnum Italiae), was a barbarian kingdom (476–493), that came into existence with the deposition of the last Roman emperor Romulus Augustulus at the battle of Ravenna in 476. The battle resulted in the self-proclamation as Rex by Odoacer. The creation of the state traditionally marks the end of the Western Roman Empire. Odoacer's Kingdom lasted until the assassination of Odoacer by Theodoric the Great, after which he proclaimed himself king of Italy and began to reign over the Ostrogothic Kingdom.