Aurelian in the context of Vandals

Diocletian (/ˌdaɪ.əˈkliːʃən/ DY-ə-KLEE-shən; Latin: Gaius Aurelius Valerius Diocletianus; Ancient Greek: Διοκλητιανός, romanized: Diokletianós; 242/245 – 311/312), nicknamed Jovius, was Roman emperor from 284 until his abdication in 305. He was born Diocles to a family of low status in the Roman province of Dalmatia. As with other Illyrian soldiers of the period, Diocles rose through the ranks of the military early in his career, serving under Aurelian and Probus, and eventually becoming a cavalry commander for the army of Emperor Carus. After the deaths of Carus and his son Numerian on a campaign in Persia, Diocles was proclaimed emperor by the troops, taking the name "Diocletianus". The title was also claimed by Carus's surviving son, Carinus, but Diocletian defeated him in the Battle of the Margus.

Diocletian's reign stabilized the empire and ended the Crisis of the Third Century. He initiated the process of the Roman Empire split and appointed fellow officer Maximian as Augustus, co-emperor, in 286. Diocletian reigned in the Eastern Empire, and Maximian reigned in the Western Empire. Diocletian delegated further on 1 March 293, appointing Galerius and Constantius as junior colleagues (each with the title Caesar), under himself and Maximian respectively. Under the Tetrarchy, or "rule of four", each tetrarch would rule over a quarter-division of the empire. Diocletian secured the empire's borders and purged it of all threats to his power. He defeated the Sarmatians and Carpi during several campaigns between 285 and 299, the Alamanni in 288, and usurpers in Egypt between 297 and 298. Galerius, aided by Diocletian, campaigned successfully against Persia, the empire's traditional enemy, and in 299, he sacked their capital, Ctesiphon. Diocletian led the subsequent negotiations and achieved a lasting and favorable peace.

The antoninianus or pre-reform radiate was a coin used during the Roman Empire thought to have been valued at 2 denarii. It was initially silver, but was slowly debased to bronze with a minimal silver content. The coin was introduced by Caracalla in early 215 AD. It was silver, similar to the denarius, except that it was slightly larger and featured the emperor wearing a radiate crown, indicating it was a double denomination. Antoniniani depicting women (usually the emperor's wife) featured the bust resting upon a crescent moon.

Even at its introduction, the silver content of the antoninianus was only equal to 1.5 denarii. This created inflation: people rapidly hoarded the denarii (Gresham's law), while both buyers and sellers recognized the new coin had a lower intrinsic value and elevated their prices to compensate. Silver bullion supplies began running short because the Roman Empire was no longer conquering new territory, the Iberian silver mines had been exhausted, and a series of soldier emperors and usurpers needed coin to pay their troops and buy their loyalty. Each new issue of the antoninianus thus had less silver in it than the last, and thus contributed to ever-increasing inflation.

The Battle of Naissus in 268 or 269 was the defeat of a Gothic coalition by the Roman Empire under Emperor Gallienus (or Emperor Claudius II Gothicus) and the future Emperor Aurelian near Naissus (Niš). The events around the invasion and the battle are an important part of the history of the Crisis of the Third Century.

The result was a great Roman victory which, combined with the effective pursuit of the invaders in the aftermath of the battle and the energetic efforts of the future Emperor Aurelian, largely removed the threat from Germanic tribes in the Balkan frontier for the following decades.

The Aurelian Walls (Italian: Mura aureliane) are a line of city walls built between 271 AD and 275 AD in Rome, Italy, during the reign of the Roman Emperor Aurelian. They superseded the earlier Servian Wall built during the 4th century BC.

The walls enclosed all the seven hills of Rome plus the Campus Martius and, on the right bank of the Tiber, the Trastevere district. The river banks within the city limits appear to have been left unfortified, although they were fortified along the Campus Martius. The size of the entire enclosed area is 1,400 hectares (3,500 acres). The wall cut through populated areas: in reality the city at the time embraced 2,400 hectares (5,900 acres). Pliny the Elder in the first century AD suggested that the densely populated areas, extrema tectorum ("the limits of the roofed areas") extended 2.8 kilometres (1.7 mi) from the Golden Milestone in the Forum (Natural History 3.67).

Marcus Aurelius Claudius Quintillus (died 270) was a short-lived Roman emperor. He took power after the death of his brother, Emperor Claudius Gothicus, in 270. After reigning for a few weeks Quintillus was overthrown by Aurelian, who had been proclaimed rival emperor by the legions he commanded. The ancient sources variously report him to have killed himself, to have fallen in battle against Aurelian, or to have been murdered by his own soldiers.

The Palmyrene Empire was a short-lived breakaway state from the Roman Empire resulting from the Crisis of the Third Century. Named after its capital city, Palmyra, it encompassed the Roman provinces of Syria Palaestina, Arabia Petraea, and Egypt, as well as large parts of Asia Minor.

The Palmyrene Empire was ruled by Queen Zenobia, officially as regent for her son Vaballathus, who inherited the throne in 267 at age ten. In 270, Zenobia rapidly conquered most of the Roman east, attempting to maintain relations with Rome as a legitimate power. In 271, she claimed the imperial title for both herself and her son, fighting a short war with the Roman emperor Aurelian, who conquered Palmyra and captured Zenobia. A year later the Palmyrenes rebelled, which led Aurelian to raze Palmyra.

Gallic Empire or Gallo-Roman Empire are names used in modern historiography for a breakaway Western European part of the Roman Empire that functioned de facto as a separate state from 260 to 274. It originated during the Crisis of the Third Century, when a series of Roman military leaders and aristocrats declared themselves emperors and took control of Gaul and adjacent provinces without attempting to conquer Italy or otherwise seize the central Roman administrative apparatus.

The Gallic Empire was established by Postumus in 260 in the wake of barbarian invasions and instability in Rome, and at its height it included the territories of Germania, Gaul, Britannia, and Hispania. After Postumus' assassination in 269 it lost much of its territory but continued under several emperors and usurpers. It was retaken by Roman Emperor Aurelian after the Battle of Châlons in 274.

The Via Nomentana was an ancient Roman road in Italy, leading North-East from Rome to Nomentum (modern Mentana), a distance of 23 km (14 mi). It originally bore the name "Via Ficulensis", from the old Latin village of Ficulea, about 13 km (8.1 mi) from Rome. It was subsequently extended to Nomentum, but never became an important high road, and merged in the Via Salaria a few kilometers beyond Nomentum. It is followed as far as Nomentum by the modern state road, but some traces of its pavement still exist.

The road started at the Porta Collina in the Servian Walls until the third century, when emperor Aurelian built the Porta Nomentana in his new set of walls.

The 3rd century was the period from AD 201 (represented by the Roman numerals CCI) to AD 300 (CCC) in accordance with the Julian calendar.

In this century, the Roman Empire saw a crisis, starting with the assassination of the Roman Emperor Severus Alexander in 235, plunging the empire into a period of economic troubles, barbarian incursions, political upheavals, civil wars, and the split of the Roman Empire through the Gallic Empire in the west and the Palmyrene Empire in the east, which all together threatened to destroy the Roman Empire in its entirety, but the reconquests of the seceded territories by Emperor Aurelian and the stabilization period under Emperor Diocletian due to the administrative strengthening of the empire caused an end to the crisis by 284. This crisis would also mark the beginning of Late Antiquity. While in North Africa, Roman rule continued with growing Christian influence, particularly in the region of Carthage.

Dacia Aureliana was a province in the eastern half of the Roman Empire established by Roman Emperor Aurelian in the territory of former Moesia Superior after his evacuation of Dacia Traiana beyond the Danube in 271. Between 271/275 and 285, it occupied most of what is today northwestern Bulgaria and eastern Serbia. Its capital was in Serdica (modern Sofia).

This province was populated with a part of the former inhabitants of Dacia Traiana. It is written in Eutropius' work: Abridgment of Roman History (9:15):

The Palmyrene alphabet was a historical Semitic alphabet used to write Palmyrene Aramaic. It was used between 100 BCE and 300 CE in Palmyra in the Syrian desert.The oldest surviving Palmyrene inscription dates to 44 BCE.The last surviving inscription dates to 274 CE, two years after Palmyra was sacked by Roman Emperor Aurelian, ending the Palmyrene Empire. Use of the Palmyrene language and script declined, being replaced with Greek and Latin.

The Palmyrene alphabet was derived from cursive versions of the Aramaic alphabet and shares many of its characteristics:

Sol Invictus (Classical Latin: [ˈsoːɫ ɪnˈwɪktʊs], "Invincible Sun" or "Unconquered Sun") was the official sun god of the late Roman Empire and a later aspect of, or replacement for, the old Latin god Sol. The emperor Aurelian revived his cult in 274 AD and promoted Sol Invictus as the chief god of the empire. From Aurelian onward, Sol Invictus often appeared on imperial coinage, usually shown wearing a sun crown and driving a horse-drawn chariot through the sky. His prominence lasted until the emperor Constantine I legalized Christianity and restricted paganism. The last known inscription referring to Sol Invictus dates to AD 387, although there were enough devotees in the fifth century that the Christian theologian Augustine found it necessary to preach against them.

In recent years, the scholarly community has become divided on Sol between traditionalists and a growing group of revisionists. In the traditional view, Sol Invictus was the second of two different sun gods in Rome. The first of these, Sol Indiges, or Sol, was believed to be an early Roman god of minor importance whose cult had petered out by the first century AD. Sol Invictus, on the other hand, was believed to be a Syrian sun god whose cult was first promoted in Rome under Elagabalus, without success. Some fifty years later, in 274 AD, Aurelian established the cult of Sol Invictus as an official religion. There has never been consensus on which Syrian sun god he might have been: some scholars opted for the sky god of Emesa, Elagabal, while others preferred Malakbel of Palmyra. In the revisionist view, there was only one cult of Sol in Rome, continuous from the monarchy to the end of antiquity. There were at least three temples of Sol in Rome, all active during the Empire and all dating from the earlier Republic.

Sremska Mitrovica (Serbian pronunciation: [srêːmskaː mîtroʋitsa]; Serbian Cyrillic: Сремска Митровица, Latin: Sirmium) is a city in Serbia. It is situated on the left bank of the Sava river. As of 2022, the city has a total population of 36,764 inhabitants, while its administrative area has a population of 72,580 inhabitants.

As Sirmium, it was a capital of the Roman Empire during the Tetrarchy of 4th century CE. Ten Roman emperors were born in or near this city, Emperors Herennius Etruscus (251), Hostilian (251), Decius Traian (249–251), Claudius Gothicus (268–270), Quintillus (270), Aurelian (270–275), Probus (276–282), Maximian (285–310), Constantius II (337–361) and Gratian (367–383).

The popularly named "Tomb of the Julii" (Mausoleum "M") survives in the Vatican Necropolis beneath St. Peter's Basilica. The serendipitous discovery near the crypt has a vaulted ceiling bearing a mosaic depicting a solar deity with an aureole riding in his chariot, within a framing of rinceaux of vine leaves.

The surrounding Christian iconography, such as other mosaics in this tomb depicting Jonah and the whale, the good shepherd carrying a lamb (the kriophoros motif), and fishermen have led to an interpretation of the deity as Christ, known in this form as "Christus-Sol" or "Christ-Apollo". Due to these symbols, the tomb is interpreted as an early Christian vault. Allen Brent has described it as a "synthesis between Christ and Apollo", in the context of Emperor Aurelian's promotion of Sol Invictus as the chief god of the Roman Empire. According to Brent, Sol Invictus - "with whom Apollo also could be identified" - represented the "shared deity of all individual gods", and the Christian creators of the Tomb of the Julii wished to "express the metaphysical order in the cosmos in terms of a Christian syncretism".

The Pincian Hill (Italian: Pincio [ˈpintʃo]; Latin: Mons Pincius) is a hill in the northeast quadrant of the historical centre of Rome. The hill lies to the north of the Quirinal, overlooking the Campus Martius. It was outside the original boundaries of the ancient city of Rome, and was not one of the Seven hills of Rome, but it lies within the wall built by Roman Emperor Aurelian between 270 and 273.

Septimia Zenobia (Palmyrene Aramaic: 𐡡𐡶𐡦𐡡𐡩‎, romanized: Bat-Zabbai; c. 240 – c. 274) was a third-century queen of the Palmyrene Empire in Syria. Many legends surround her ancestry; she was probably not a commoner, and she married Odaenathus, the ruler of the city of Palmyra. Her husband became king of Palmyra in 260, elevating Palmyra to supreme power in the Near East by defeating the Sasanian Empire of Persia and stabilizing the Roman East. After Odaenathus' assassination in 267, Zenobia became the regent of her son Vaballathus and held de facto power throughout his reign (267 to 272).

In 270, Zenobia launched an invasion that brought most of the Roman East under her sway and culminated with the annexation of Egypt. By mid-271 her realm extended from Ancyra, central Anatolia, to Upper Egypt, although she remained nominally subordinate to Rome. However, in reaction to the campaign of the Roman emperor Aurelian in 272, Zenobia declared her son emperor and assumed the title of empress, thus declaring Palmyra's secession from Rome. The Romans were victorious after heavy fighting; the empress was besieged in her capital and captured in late 272 by Aurelian, who exiled her to Rome, where she spent the remainder of her life.

48°57′27″N 4°21′54″E / 48.9575°N 4.365°E / 48.9575; 4.365

In the Battle of Châlons, fought in 274 on the site of modern Châlons-en-Champagne, France, Roman Emperor Aurelian defeated Emperor Tetricus I of the Gallic Empire, whose territories were rejoined with the Roman Empire after 14 years of separation.