Principate in the context of "Roman historiography"

The Roman Senate (Latin: Senātus Rōmānus) was the highest and constituting assembly of ancient Rome and its aristocracy. With different powers throughout its existence, it lasted from the first days of the city of Rome (traditionally founded in 753 BC) as the Senate of the Roman Kingdom, to the Senate of the Roman Republic and Senate of the Roman Empire and eventually the Byzantine Senate of the Eastern Roman Empire, existing well into the post-classical era and Middle Ages.

During the days of the Roman Kingdom, the Senate was generally little more than an advisory council to the king. However, as Rome was an electoral monarchy, the Senate also elected new Roman kings. The last king of Rome, Lucius Tarquinius Superbus, was overthrown following a coup d'état led by Lucius Junius Brutus, who founded the Roman Republic. During the early Republic, the Senate was politically weak, while the various executive Roman magistrates who appointed the senators for life (or until expulsion by Roman censors) were quite powerful. Since the transition from monarchy to constitutional rule was most likely gradual, it took several generations before the Senate was able to assert itself over the executive magistrates. By the middle Republic, the Senate had reached the apex of its republican power. The late Republic saw a decline in the Senate's power, which began following the reforms of the tribunes Tiberius and Gaius Gracchus. After the transition of the Republic into the Principate, the Senate lost much of its political power as well as its prestige.

Augustus (born Gaius Octavius; 23 September 63 BC – 19 August AD 14), also known as Octavian (Latin: Octavianus), was the founder of the Roman Empire, who reigned as the first Roman emperor from 27 BC until his death in AD 14. The reign of Augustus initiated an imperial cult and an era of imperial peace (the Pax Romana or Pax Augusta) in which the Roman world was largely free of armed conflict. The Principate system of government was established during his reign and lasted until the Crisis of the Third Century.

Octavian was born into an equestrian branch of the plebeian gens Octavia. Following the assassination of Julius Caesar in 44 BC, Octavian was named in Caesar's will as his adopted son and heir, and inherited Caesar's name, estate, and the loyalty of his legions. He, Mark Antony, and Marcus Lepidus formed the Second Triumvirate to defeat the assassins of Caesar. Following their victory at the Battle of Philippi (42 BC), the Triumvirate divided the Roman Republic among themselves and ruled as de facto oligarchs. The Triumvirate was eventually torn apart by the competing ambitions of its members; Lepidus was exiled in 36 BC, and Antony was defeated by Octavian's naval commander Marcus Agrippa at the Battle of Actium in 31 BC. Antony and his wife Cleopatra, the Ptolemaic queen of Egypt, killed themselves during Octavian's invasion of Egypt, which then became a Roman province.

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.

In modern scholarship, the "late" period of the Roman army begins with the accession of the Emperor Diocletian in AD 284, and ends in 480 with the death of Julius Nepos, being roughly coterminous with the Dominate. During the period 395–476, the army of the Roman Empire's western half progressively disintegrated, while its counterpart in the East, known as the East Roman army (or the early Byzantine army) remained largely intact in size and structure until the reign of Justinian I (r. AD 527–565).

The Imperial Roman army of the Principate (30 BC – 284 AD) underwent a significant transformation as a result of the chaotic 3rd century. Unlike the army of the Principate, the army of the 4th century was heavily dependent on conscription and its soldiers were paid much less than in the 2nd century. Barbarians from outside the empire probably supplied a much larger proportion of the late army's recruits than in the army of the 1st and 2nd centuries, but there is little evidence that this adversely affected the army's combat performance.

The constitution of the late Roman Empire was an unwritten set of guidelines and principles passed down, mainly through precedent, which defined the manner in which the late Roman Empire was governed. As a matter of historical convention, the late Roman Empire emerged from the Roman Principate (the early Roman Empire), with the accession of Diocletian in AD 284, his reign marking the beginning of the Tetrarchy. The constitution of the Dominate outrightly recognized monarchy as the true source of power, and thus ended the facade of dyarchy, in which emperor and Senate governed the empire together.

Diocletian's reforms to the Imperial government finally put an end to the period when the old Republican magistracies (e.g. consuls and praetors) held real powers. From then, the consuls had almost no real duties beyond that of presiding at Senate meetings and the duties of the lesser magistrates were effectively just hosting various games, e.g. chariot racing. Most other lesser magistracies simply disappeared.

Antioch on the Orontes (/ˈænti.ɒk/ ; Ancient Greek: Ἀντιόχεια ἡ ἐπὶ Ὀρόντου, romanized: Antiókheia hē epì Oróntou, pronounced [anti.ó.kʰeː.a]) was a Hellenistic Greek city founded by Seleucus I Nicator in 300 BC. One of the most important Greek cities of the Hellenistic period, it served as the capital of the Seleucid Empire and later as regional capital to both the Roman and Byzantine Empire. During the Crusades, Antioch served as the capital of the Principality of Antioch, one of four Crusader states that were founded in the Levant. Its inhabitants were known as Antiochenes. The remains of the ancient city of Antioch are mostly buried beneath alluvial deposits from the Orontes River. The modern city of Antakya, in Hatay Province of Turkey, lies in its place.

Antioch was founded near the end of the 4th century BC by Seleucus I Nicator, one of Alexander the Great's generals, as one of the tetrapoleis of Seleucis of Syria. Seleucus encouraged Greeks from all over the Mediterranean to settle in the city. The city's location offered geographical, military, and economic benefits to its occupants; Antioch was heavily involved in the spice trade and lay within close reach of the Silk Road and the Royal Road. The city was the capital of the Seleucid Empire from 240 BC until 63 BC, when the Romans took control, making it the capital of the province of Syria and later of Coele Syria. During the late Hellenistic and Roman Principate periods, Antioch's population may have reached a peak of over 500,000 inhabitants (most generally estimate between 200,000 and 250,000), making the city the third largest in the Roman Empire after Rome and Alexandria and one of the most important cities in the eastern Mediterranean. From the early 4th century, Antioch was the seat of the comes Orientis, head of the Diocese of the East. The Romans provided the city with walls that encompassed almost 450 hectares (1,100 acres).

Julius Caesar, the Roman dictator, was assassinated on the Ides of March (15 March), 44 BC, by a group of senators during a Senate session at the Curia of Pompey, located within the Theatre of Pompey in Rome. The conspirators, numbering between 60 and 70 individuals and led by Marcus Junius Brutus, Gaius Cassius Longinus, and Decimus Junius Brutus Albinus, stabbed Caesar approximately 23 times. They justified the act as a preemptive defense of the Roman Republic, asserting that Caesar's accumulation of lifelong political authority—including his perpetual dictatorship and other honors—threatened republican traditions.

The assassination failed to achieve its immediate objective of restoring the Republic's institutions. Instead, it precipitated Caesar's posthumous deification, triggered the Liberators' civil war (43–42 BC) between his supporters and the conspirators, and contributed to the collapse of the Republic. These events ultimately culminated in the rise of the Roman Empire under Augustus, marking the beginning of the Principate era.