Roman emperor in the context of Gratianus Funarius

The fall of the Western Roman Empire, also called the fall of the Roman Empire or the fall of Rome, was the loss of central political control in the Western Roman Empire, a process in which the Empire failed to enforce its rule, and its vast territory was divided among several successor polities. The Roman Empire lost the strengths that had allowed it to exercise effective control over its Western provinces; modern historians posit factors including the effectiveness and numbers of the army, the health and numbers of the Roman population, the strength of the economy, the competence of the emperors, the internal struggles for power, the religious changes of the period, and the efficiency of the civil administration. Increasing pressure from invading peoples outside Roman culture also contributed greatly to the collapse. Climatic changes and both endemic and epidemic disease drove many of these immediate factors. The reasons for the collapse are major subjects of the historiography of the ancient world and they inform much modern discourse on state failure.

In 376, a large migration of Goths and other non-Roman people, fleeing from the Huns, entered the Empire. Roman forces were unable to exterminate, expel or subjugate them (as was their normal practice). In 395, after winning two destructive civil wars, Theodosius I died. He left a collapsing field army, and the Empire divided between the warring ministers of his two incapable sons. Goths and other non-Romans became a force that could challenge either part of the Empire. Further barbarian groups crossed the Rhine and other frontiers. The armed forces of the Western Empire became few and ineffective, and despite brief recoveries under able leaders, central rule was never again effectively consolidated.

Basil II Porphyrogenitus (Greek: Βασίλειος Πορφυρογέννητος, romanized: Basíleios Porphyrogénnētos; 958 – 15 December 1025), nicknamed the Bulgar Slayer (Greek: ὁ Βουλγαροκτόνος, ho Boulgaroktónos, Bulgarian: Българоубиец), was the senior Byzantine emperor from 976 to 1025. He and his brother Constantine VIII were crowned before their father Romanos II died in 963, but they were too young to rule. The throne thus went to two generals, Nikephoros Phokas (r. 963–969) and John Tzimiskes (r. 969–976) before Basil became senior emperor, though his influential great-uncle Basil Lekapenos remained as the de facto ruler until 985. His reign of 49 years and 11 months was the longest of any Roman emperor.

The early years of Basil's reign were dominated by civil wars against two powerful generals from the Byzantine Anatolian aristocracy: first Bardas Skleros and later Bardas Phokas, which ended shortly after Phokas' death and Skleros' submission in 989. Basil then oversaw the stabilization and expansion of the eastern frontier of the Byzantine Empire and the complete subjugation of the First Bulgarian Empire, its foremost European foe, after a long struggle. Although the Byzantines had made a truce with the Fatimid Caliphate in 987–988, Basil led a campaign against the Caliphate that ended with another truce in 1000. He also conducted a campaign against the Khazar Khaganate that gained the Byzantine Empire part of Crimea and a series of successful campaigns against the Kingdom of Georgia.

Aelius Galenus or Claudius Galenus (Greek: Κλαύδιος Γαληνός; September 129 – c. 216 AD), often anglicized as Galen (/ˈɡeɪlən/) or Galen of Pergamon, was a Roman and Greek physician, surgeon, and philosopher. Considered to be one of the most accomplished of all medical researchers of antiquity, Galen influenced the development of various scientific disciplines, including anatomy, physiology, pathology, pharmacology, and neurology, as well as philosophy and logic.

The son of Aelius Nicon, a wealthy Greek architect with scholarly interests, Galen received a comprehensive education that prepared him for a successful career as a physician and philosopher. Born in the ancient city of Pergamon (present-day Bergama, Turkey), Galen traveled extensively, exposing himself to a wide variety of medical theories and discoveries before settling in Rome, where he served prominent members of Roman society and eventually was given the position of personal physician to several emperors.

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.

Augustus (plural Augusti; /ɔːˈɡʌstəs/ aw-GUST-əs, Classical Latin: [au̯ˈɡʊstʊs]; "majestic", "great" or "venerable") was the main title of the Roman emperors during Antiquity. It was given as both name and title to Gaius Julius Caesar Octavianus (often referred to simply as Augustus) in 27 BC, marking his accession as Rome's first emperor. On his death, it became an official title of his successor, and was so used by all emperors thereafter. The feminine form Augusta was used for Roman empresses and other female members of the imperial family. The masculine and feminine forms originated in the time of the Roman Republic, in connection with things considered divine or sacred in traditional Roman religion. Their use as titles for major and minor Roman deities of the Empire associated the imperial system and family with traditional Roman virtues and the divine will and may be considered a feature of the Roman imperial cult.

In Rome's Greek-speaking provinces, "Augustus" was translated as Sebastos (Σεβαστός), or Hellenised as Augoustos (Αὔγουστος); these titles continued to be used in the Byzantine Empire until the Fall of Constantinople in 1453, although they gradually lost their imperial exclusivity in favour of Basileus and Autokrator.

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.

Constantine I (27 February 272 – 22 May 337), also known as Constantine the Great, or known mononymously as Constantine, was Roman emperor from AD 306 to 337 and the first Roman emperor to convert to Christianity. He played a pivotal role in elevating the status of Christianity in Rome, the Edict of Milan decriminalising Christian practice and ceasing Christian persecution. This was a turning point in the Christianisation of the Roman Empire. He founded the city of Constantinople (now Istanbul) and made it the capital of the Empire, which it remained for over a millennium.

Born in Naissus, a city located in the province of Moesia Superior (now Niš, Serbia), Constantine was the son of Flavius Constantius, a Roman army officer from Moesia Superior, who would become one of the four emperors of the Tetrarchy. His mother, Helena, was a woman of low birth, probably from Bithynia. Later canonised as a saint, she is credited for the conversion of her son in some traditions, though others believe that Constantine converted her. He served with distinction under emperors Diocletian and Galerius. He began his career by campaigning in the eastern provinces against the Persians, before being recalled to the west in AD 305 to fight with his father in the province of Britannia. After his father's death in 306, Constantine was proclaimed as augustus (emperor) by his army at Eboracum (York, England). He eventually emerged victorious in Civil wars of the Tetrarchy against the emperors Maxentius and Licinius to become the sole ruler of the Roman Empire by 324.

Theodosius I (Ancient Greek: Θεοδόσιος Theodosios; 11 January 347 – 17 January 395), also known as Theodosius the Great, was Roman emperor from 379 to 395. He won two civil wars and was instrumental in establishing the Nicene Creed as the orthodox doctrine for Nicene Christianity. Theodosius was the last emperor to rule the entire Roman Empire before its administration was permanently split between the Western Roman Empire and the Eastern Roman Empire. He ended the Gothic War (376–382), but did so on terms disadvantageous to the empire, with the Goths remaining and politically autonomous within Roman territory, albeit as nominal allies.

Born in Hispania, Theodosius was the son of a high-ranking general of the same name, Theodosius the Elder, under whose guidance he rose through the ranks of the Roman army. Theodosius held independent command in Moesia in 374, where he had some success against the invading Sarmatians. Not long afterwards, he was forced into retirement, and his father was executed under obscure circumstances. Theodosius soon regained his position following a series of intrigues and executions at Emperor Gratian's court. In 379, after the eastern Roman emperor Valens was killed at the Battle of Adrianople against the Goths, Gratian appointed Theodosius as a successor with orders to take charge of the military emergency. The new emperor's resources and depleted armies were not sufficient to drive the invaders out; in 382 the Goths were allowed to settle south of the Danube as autonomous allies of the empire. In 386, Theodosius signed a treaty with the Sasanian Empire which partitioned the long-disputed Kingdom of Armenia and secured a durable peace between the two powers.

Trajan (/ˈtreɪdʒən/ TRAY-jən; born Marcus Ulpius Traianus, 18 September 53 – c. 9 August 117) was a Roman emperor from AD 98 to 117, remembered as the second of the Five Good Emperors of the Nerva–Antonine dynasty. He was a philanthropic ruler and a successful soldier-emperor who presided over one of the greatest military expansions in Roman history, during which, by the time of his death, the Roman Empire reached its maximum territorial extent. He was given the title of Optimus ('the best') by the Roman Senate.

Trajan was born in the municipium of Italica in the present-day Andalusian province of Seville in southern Spain, an Italic settlement in Hispania Baetica; his gens Ulpia came from the town of Tuder in the Umbria region of central Italy. His namesake father, Marcus Ulpius Traianus, was a general and distinguished senator. Trajan rose to prominence during the reign of Domitian; in AD 89, serving as a legatus legionis in Hispania Tarraconensis, he supported the emperor against a revolt on the Rhine led by Antonius Saturninus. He then served as governor of Germania and Pannonia. In September 96, Domitian was succeeded by the elderly and childless Nerva, who proved to be unpopular with the army. After a revolt by members of the Praetorian Guard, Nerva decided to adopt as his heir and successor the more popular Trajan, who had distinguished himself in military campaigns against Germanic tribes.

Heracles (/ˈhɛrəkliːz/ Ancient Greek: Ἡρακλῆς, lit. 'glory/fame of Hera'), born Alcaeus (Ἀλκαῖος, Alkaios) or Alcides (Ἀλκείδης, Alkeidēs), was a divine hero in Greek mythology, the son of Zeus and Alcmene, and the foster son of Amphitryon. He was a descendant of Perseus, another son of Zeus.

He was the greatest of the Greek heroes, the ancestor of royal clans known as Heracleidae (Ἡρακλεῖδαι), and a champion of the Olympian order against chthonic monsters. In Rome and the modern West, he is known as Hercules, with whom the later Roman emperors, in particular Commodus and Maximian, often identified themselves. Details of his cult were adapted to Rome as well.

Marcus Aurelius Antoninus (/ɔːˈriːliəs/ or-EE-lee-əs, Latin: [ˈmaːrkʊs au̯ˈreːli.us antoːˈniːnʊs]; 26 April 121 – 17 March 180) was Roman emperor from 161 to 180 and a Stoic philosopher. He was a member of the Nerva–Antonine dynasty, the last of the rulers later known as the Five Good Emperors and the last emperor of the Pax Romana, an age of relative peace, calm, and stability for the Roman Empire lasting from 27 BC to 180 AD. He served as Roman consul in 140, 145, and 161.

Marcus Aurelius was the son of the praetor Marcus Annius Verus and his wife, Domitia Calvilla. He was related through marriage to the emperors Trajan and Hadrian. Marcus was three when his father died, and was raised by his mother and paternal grandfather. After Hadrian's adoptive son, Aelius Caesar, died in 138, Hadrian adopted Marcus's uncle Antoninus Pius as his new heir. In turn, Antoninus adopted Marcus and Lucius, the son of Aelius. Hadrian died that year, and Antoninus became emperor. Now heir to the throne, Marcus studied Greek and Latin under tutors such as Herodes Atticus and Marcus Cornelius Fronto. He married Antoninus's daughter Faustina in 145.

Alaric I (/ˈælərɪk/; Gothic: 𐌰𐌻𐌰𐍂𐌴𐌹𐌺𐍃, Alarīks lit.'ruler of all'; Latin: Alaricus; c. 370 – 411 AD) was the first king of the Visigoths, from 395 to 410. He rose to leadership of the Goths who came to occupy Moesia—territory acquired a couple of decades earlier by a combined force of Goths and Alans after the Battle of Adrianople.

Alaric began his career under the Gothic soldier Gainas and later joined the Roman army. Once an ally of Rome under the Roman emperor Theodosius, Alaric helped defeat the Franks and other allies of a would-be Roman usurper. Despite losing many thousands of his men, he received little recognition from Rome and left the Roman army disappointed. After the death of Theodosius and the disintegration of the Roman armies in 395, he is described as king of the Visigoths. As the leader of the only effective field force remaining in the Balkans, he sought Roman legitimacy, never quite achieving a position acceptable to himself or to the Roman authorities.

Justinian I (Latin: Iustinianus, Ancient Greek: Ἰουστινιανός, romanized: Ioustinianós; 482 – 14 November 565), also known as Justinian the Great, was Roman emperor from 527 to 565.

His reign was marked by the ambitious but only partly realized renovatio imperii, or "restoration of the Empire". This ambition was expressed by the partial recovery of the territories of the defunct Western Roman Empire. His general, Belisarius, swiftly conquered the Vandal Kingdom in North Africa. Subsequently, Belisarius, Narses, and other generals conquered the Ostrogothic Kingdom, restoring Dalmatia, Sicily, Italy, and Rome to the empire after more than half a century of rule by the Ostrogoths. The praetorian prefect Liberius reclaimed the south of the Iberian Peninsula, establishing the province of Spania. These campaigns re-established Roman control over the western Mediterranean, increasing the Empire's annual revenue by over a million solidi. During his reign, Justinian also subdued the Tzani, a people on the east coast of the Black Sea that had never been under Roman rule before. He engaged the Sasanian Empire in the east during Kavad I's reign, and later again during Khosrow I's reign; this second conflict was partially initiated due to his ambitions in the west.

Cleopatra VII, the last ruler of the Ptolemaic Kingdom of Egypt, died on either 10 or 12 August, 30 BC, in Alexandria, when she was 39 years old. According to popular belief, Cleopatra killed herself by allowing an asp (Egyptian cobra) to bite her, but according to the Roman-era writers Strabo, Plutarch, and Cassius Dio, Cleopatra poisoned herself using either a toxic ointment or by introducing the poison with a sharp implement such as a hairpin. Modern scholars debate the validity of ancient reports involving snakebites as the cause of death and whether she was murdered. Some academics hypothesize that her Roman political rival Augustus (Octavian) forced her to kill herself in a manner of her choosing. The location of Cleopatra's tomb is unknown. It was recorded that Octavian allowed for her and her husband, the Roman politician and general Mark Antony, who stabbed himself with a sword, to be buried together properly.

Cleopatra's death effectively ended the final war of the Roman Republic between the remaining triumvirs Octavian and Antony, in which Cleopatra aligned herself with Antony, father to three of her children. Antony and Cleopatra fled to Egypt following their loss at the 31 BC Battle of Actium in Roman Greece, after which Octavian invaded Egypt and defeated their forces. Committing suicide allowed her to avoid the humiliation of being paraded as a prisoner in a Roman triumph celebrating the military victories of Octavian, who would become Rome's first emperor in 27 BC and be known as Augustus. Octavian, rival heir of Julius Caesar had Cleopatra's son Caesarion (also known as Ptolemy XV) killed in Egypt but spared her children with Antony and brought them to Rome. Cleopatra's death marked the end of the Hellenistic period and Ptolemaic rule of Egypt, as well as the beginning of Roman Egypt, which became a province of the Roman Empire.

Marcus Aurelius Antoninus (born Lucius Septimius Bassianus, 4 April 188 – 8 April 217), better known by his nickname Caracalla (/ˌkærəˈkælə/; Latin: [karaˈkalːa]), was Roman emperor from 198 to 217 AD, first serving as nominal co-emperor under his father and then ruling alone after 211 AD. He was a member of the Severan dynasty, the elder son of Emperor Septimius Severus and Empress Julia Domna. Severus proclaimed Caracalla co-ruler in 198, doing the same with his other son Geta in 209. The two brothers briefly shared power after their father's death in 211, but Caracalla soon had Geta murdered by the Praetorian Guard and became sole ruler of the Roman Empire. Julia Domna had a significant share in governance, since Caracalla found administration to be mundane. His reign featured domestic instability and external invasions by the Germanic peoples.

Caracalla issued the Antonine Constitution (Latin: Constitutio Antoniniana), also known as the Edict of Caracalla, which granted Roman citizenship to all free men throughout the Roman Empire. The edict gave all the enfranchised men Caracalla's adopted praenomen and nomen: "Marcus Aurelius". Other landmarks of his reign were the construction of the Baths of Caracalla, the second-largest bathing complex in the history of Rome, the introduction of a new Roman currency named the antoninianus, a sort of double denarius, and the massacres he ordered, both in Rome and elsewhere in the empire. In 216, Caracalla began a campaign against the Parthian Empire. He did not see this campaign through to completion due to his assassination by a disaffected soldier in 217. Macrinus succeeded him as emperor three days later.

The Constitutio Antoniniana (Latin for "Constitution [or Edict] of Antoninus"), also called the Edict of Caracalla or the Antonine Constitution, was an edict issued in AD 212 by the Roman emperor Caracalla. It declared that all free men in the Roman Empire were to be given full Roman citizenship (and by extension all free women in the Empire were to be given the same rights as Roman women, such as the jus trium liberorum).

Before AD 212, full Roman citizenship was mostly only held by inhabitants of Roman Italy. Colonies of Romans established in the provinces, Romans (or their descendants) living in provinces, the inhabitants of various cities throughout the Empire, and small numbers of local nobles (such as kings of client countries) also held full citizenship. Provincials, on the other hand, were usually non-citizens, although some held the Latin rights. Veterans of the Auxilia were also granted Roman citizenship on discharge. Being a Roman citizen remained a well sought-after status until 212.

Tiberius Claudius Caesar Augustus Germanicus (/ˈklɔːdiəs/ KLAW-dee-əs; Classical Latin: [tɪˈbɛri.ʊs ˈkɫau̯di.ʊs ˈkae̯sar au̯ˈɡʊstʊs ɡɛrˈmaːnɪkʊs]; 1 August 10 BC – 13 October AD 54), or Claudius, was a Roman emperor, ruling from AD 41 to 54. A member of the Julio-Claudian dynasty, Claudius was born to Drusus and Antonia Minor at Lugdunum in Roman Gaul, where his father was stationed as a military legate. He was the first Roman emperor to be born outside Italy.

As he had a limp, a stammer, and a tremor due to an illness he suffered when young, he was ostracized by his family and was excluded from public office until his consulship (which was shared with his nephew, Caligula, in 37). Claudius's infirmity probably saved him from the fate of many other nobles during the purges throughout the reigns of Tiberius and Caligula, as potential enemies did not see him as a serious threat. His survival led to him being declared emperor by the Praetorian Guard after Caligula's assassination, at which point he was the last adult male of his family.

Hadrian (/ˈheɪdriən/ HAY-dree-ən; born Publius Aelius Hadrianus, 24 January 76 – 10 July 138) was Roman emperor from 117 to 138. Hadrian was born in Italica, in the present-day Andalusian province of Seville in southern Spain, an Italic settlement in Hispania Baetica; his gens Aelia came from the town of Hadria in eastern Italy. He was a member of the Nerva–Antonine dynasty.

Early in his political career, Hadrian married Vibia Sabina, grandniece of the ruling emperor, Trajan, and his second cousin once removed. The marriage and Hadrian's later succession as emperor were probably promoted by Trajan's wife Pompeia Plotina. Soon after his own succession, Hadrian had four leading senators unlawfully put to death, probably because they seemed to threaten the security of his reign; this earned him the senate's lifelong enmity. He earned further disapproval by abandoning Trajan's expansionist policies and territorial gains in Mesopotamia, Assyria, Armenia, and parts of Dacia. Hadrian preferred to invest in the development of stable, defensible borders and the unification of the Roman empire's disparate peoples and subjects. He was a promoter of philhellenism.

The Fasti Capitolini, or Capitoline Fasti, are a list of the chief magistrates of the Roman Republic, extending from the early fifth century BC down to the reign of Augustus, the first Roman emperor. Together with similar lists found at Rome and elsewhere, they form part of a chronology referred to as the Fasti Annales, Fasti Consulares, or Consular Fasti, or occasionally just the fasti.

The Capitoline Fasti were originally engraved on marble tablets erected in the Roman forum. The main portions were discovered in a fragmentary condition, and removed from the forum in 1546, as ancient structures were dismantled to produce material for the construction of St. Peter's Basilica. They were brought to the Palazzo dei Conservatori on the adjacent Capitoline Hill, where they remain as part of the collection of the Capitoline Museums, together with other Roman antiquities. Together with the histories of writers such as Livy and Dionysius of Halicarnassus, the Capitoline Fasti form one of the primary sources for Roman chronology.