Galerius in the context of Caesar (title)

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.

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.

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 Tetrarchy was the system instituted by Roman emperor Diocletian to govern the ancient Roman Empire by dividing it between two emperors, the augusti, and their junior colleagues and designated successors, the caesares. It was kept in place between AD 293 and 313.

Initially Diocletian chose Maximian as his caesar in 285, raising him to co-augustus the following year; Maximian was to govern the western provinces and Diocletian would administer the eastern ones. The role of the augustus was likened to Jupiter, while his caesar was akin to Jupiter's son Hercules. Galerius and Constantius were appointed caesares in March 293. Diocletian and Maximian retired on 1 May 305, raising Galerius and Constantius to the rank of augustus. Their places as caesares were in turn taken by Valerius Severus and Maximinus Daza.

The Edict of Milan (Latin: Edictum Mediolanense; Greek: Διάταγμα τῶν Μεδιολάνων, Diatagma tōn Mediolanōn) was the February 313 agreement to treat Christians benevolently within the Roman Empire. Western Roman Emperor Constantine I and Emperor Licinius, who controlled the Balkans, met in Mediolanum (modern-day Milan) and, among other things, agreed to change policies towards Christians following the edict of toleration issued by Emperor Galerius two years earlier in Serdica. The Edict of Milan gave Christianity legal status and a reprieve from persecution but did not make it the state church of the Roman Empire, which occurred in AD 380 with the Edict of Thessalonica, when Nicene Christianity received normative status.

The document is found in Lactantius's De mortibus persecutorum and in Eusebius of Caesarea's History of the Church with marked divergences between the two. Whether or not there was a formal 'Edict of Milan'  is no longer really debated among scholars, who generally reject the story as it has come down in church history.

Early Christians were heavily persecuted throughout the Roman Empire until the 3rd century. Although Christianity initially emerged as a small Jewish movement in 1st-century Judaea, it quickly branched off as a separate religion and began spreading across the various Roman territories at a pace that put it at odds with the well-established Roman imperial cult, to which it stood in opposition; Christians were vocal in their expressions of abhorrence towards the beliefs and practices of Roman paganism, such as deifying and making ritual sacrifices to the Roman emperor or partaking in other methods of idolatry. Consequently, the Roman state and other members of civic society routinely punished Christians for treason, various rumoured crimes, illegal assembly, and for introducing an alien cult that drove many Roman people to apostasy in favour of Jesus Christ. According to Tacitus, the first wave of organized persecution occurred under Nero (r. 54–68), who blamed Christians for the Great Fire of Rome in 64. A number of mostly localized persecutions occurred during the reign of Marcus Aurelius (r. 161–180). After a lull, persecution resumed under Decius (r. 249–251) and Trebonianus Gallus (r. 251–253). The Decian persecution was particularly extensive, as Decius strived to restore the Roman golden age in part by forcing pagan practices upon the Christian community. Another wave of persecution began under Valerian (r. 253–260), but ceased abruptly after he was captured and taken prisoner by the Sasanian Empire during the Battle of Edessa of the Roman–Persian Wars. Under his successor Gallienus (r. 253–268), whose reign was marred by rapidly escalating military conflicts of the Crisis of the Third Century, the first ever decree of tolerance was issued for Christian practices and places of worship, although it stopped short of recognizing Christianity as a religion with legal status.

Emperor Diocletian (r. 283–305) began the Diocletianic persecution, which was the final and the most severe wave of persecution of Christians by the Roman state. It was enforced until the accession of Galerius (r. 305–311), who issued the Edict of Serdica, and the death of Maximinus Daza (r. 310–313). After Constantine the Great (r. 306–337) defeated his rival Maxentius (r. 306–312) at the Battle of the Milvian Bridge in October 312, he and his co-emperor Licinius issued the Edict of Milan, which decriminalized Christianity and suppressed pagan populations throughout the Roman Empire. In 380, Theodosius I (r. 379–395) issued the Edict of Thessalonica, officially establishing Christianity as the Roman state religion. It was also during the reign of Theodosius I that pagan practices were overtly deemed punishable offenses, which laid the framework for early Byzantine anti-pagan policies.

Marcus Aurelius Valerius Maxentius (c. 283 – 28 October 312) was a Roman emperor from 306 until his death in 312. Despite ruling in Italy and North Africa, and having the recognition of the Senate in Rome, he was not recognized as a legitimate emperor by his fellow emperors.

He was the son of former Emperor Maximian and the son-in-law of Emperor Galerius. The latter part of his reign was preoccupied with civil war, allying with Maximinus against Licinius and Constantine. The latter defeated him at the Battle of the Milvian Bridge in 312, where Maxentius, with his army in flight, purportedly perished by drowning in the Tiber river.

Galerius Valerius Maximinus, born as Daza (Ancient Greek: Μαξιμίνος; 20 November c. 270 – c. July 313), was Roman emperor from 310 to 313. In 305 his uncle Galerius admitted him to the Tetrarchy with the rank of caesar, a controversial appointment which helped start the civil wars of the Tetrarchy in the following year. Maximinus Daza claimed the title of augustus in 310, sharing and often contesting power with Licinius. A committed pagan, he engaged in one of the last persecutions of Christians, and was the last person to hold the title of Pharaoh of Egypt. In 313 Maximinus Daza openly turned against Licinius and was routed at the Battle of Tzirallum. He died during the subsequent retreat, shortly after publishing an edict of tolerance restoring the Christians' freedoms.

Zaječar (Serbian Cyrillic: Зајечар, pronounced [zâjɛtʃar]; Romanian: Zaicear or Zăiceari) is a city and the administrative center of the Zaječar District in eastern Serbia. According to the 2022 census, the city administrative area had a population of 48,621 inhabitants. Zaječar is widely known for its rock music festival Gitarijada and for the ZALET festival dedicated to contemporary art. Roman Emperor Galerius was born in Gamzigrad, near Zaječar, where he built the city of Felix Romuliana.

Lucius Domitius Alexander (died c. 310), probably born in Phrygia, was vicarius of Africa when Emperor Maxentius ordered him to send his son as hostage to Rome. Alexander refused and proclaimed himself emperor in 308.

The most detailed if somewhat confusing description of the insurrection is given by Zosimus (II, 12 and 14). He reports that Maxentius sent his portrait to Africa to gain recognition as Emperor there. The troops resisted because of their loyalty to Galerius. Maxentius ordered Domitius Alexander, the vicar of Africa, to send his son to Rome to secure his loyalty. Alexander refused and was crowned Emperor by his army. The incident was probably caused by the conflict between Maxentius and his father Maximian in April 308, and Zosimos confused Galerius with Maximian in his account.

The Edict of Serdica, also called Edict of Toleration by Galerius, was issued in 311 in Serdica (now Sofia, Bulgaria) by Roman Emperor Galerius. It officially ended the Diocletianic Persecution of Christianity in the Eastern Roman Empire.

The Edict implicitly granted Christianity the status of religio licita, a worship that was recognized and accepted by the Roman Empire. It was the first edict legalizing Christianity and preceded the Edict of Milan by two years.

The Diocletianic or Great Persecution was the last and most severe persecution of Christians in the Roman Empire. In 303, the emperors Diocletian, Maximian, Galerius, and Constantius issued a series of edicts rescinding Christians' legal rights and demanding that they comply with traditional religious practices. Later edicts targeted the clergy and demanded universal sacrifice, ordering all inhabitants to sacrifice to the Roman gods (Jews were exempt). The persecution varied in intensity across the empire—weakest in Gaul and Britain, where only the first edict was applied, and strongest in the Eastern provinces. Persecutory laws were nullified by different emperors (Galerius with the Edict of Serdica in 311) at different times, but Constantine and Licinius' Edict of Milan in 313 has traditionally marked the end of the persecution.

Christians had been subject to intermittent local discrimination in the empire, but emperors prior to Diocletian were reluctant to issue general laws against the religious group. In the 250s, under the reigns of Decius and Valerian, Roman subjects including Christians were compelled to sacrifice to Roman gods or face imprisonment and execution, but there is no evidence that these edicts were specifically intended to attack Christianity. After Gallienus's accession in 260, these laws went into abeyance. Diocletian's assumption of power in 284 did not mark an immediate reversal of imperial inattention to Christianity, but it did herald a gradual shift in official attitudes toward religious minorities. In the first fifteen years of his rule, Diocletian purged the army of Christians, condemned Manicheans to death, and surrounded himself with public opponents of Christianity. Diocletian's preference for activist government, combined with his self-image as a restorer of past Roman glory, foreboded the most pervasive persecution in Roman history. In the winter of 302, Galerius urged Diocletian to begin a general persecution of the Christians. Diocletian was wary and asked the oracle at Didyma for guidance. The oracle's reply was read as an endorsement of Galerius's position, and a general persecution was called on 23 February 303.

Sergius (or Serge) and Bacchus (Greek: Σέργιος & Βάκχος; Classical Syriac: ܣܪܓܝܤ ܘܒܟܘܤ, romanized: Sargīs wa Bākūs; Arabic: سركيس و باخوس, romanized: Sarkīs wa Bākhūs, also called Arabic: سرجيس و باكوس, romanized: Sarjīs wa Bākūs) were fourth-century Syrian Christian soldiers revered as martyrs and military saints by the Catholic, Eastern Orthodox and Oriental Orthodox Churches. Their feast day is 7 October.

According to their hagiography, Sergius and Bacchus were military officers in the army of the Roman Emperor Galerius and were held high in his favor until they were exposed as secret Christians. They were then severely humiliated and punished, forced to wear both feminine and commoner garments, with Bacchus dying during torture to his feet, and Sergius eventually decapitated.

Gamzigrad (Serbian Cyrillic: Гамзиград, pronounced [ɡǎmziɡraːd] ) is an archaeological site, spa resort, and UNESCO World Heritage Site of Serbia, located south of the Danube river, in the city of Zaječar. It is the location of the ancient Roman complex of palaces and temples Felix Romuliana (Serbian: Феликс Ромулијана / Feliks Romulijana), built by Emperor Galerius in Dacia Ripensis. The main area covers 10 acres (40,000 m).