* Adrian of Nicomedia ( died 306 ), martyr and Herculian Guard of the Roman Emperor Galerius Maximian

Narseh moved south into Roman Mesopotamia in 297, where he inflicted a severe defeat on Galerius in the region between Carrhae ( Harran, Turkey ) and Callinicum ( Ar-Raqqah, Syria ) ( and thus, the historian Fergus Millar notes, probably somewhere on the Balikh River ).

Narseh retreated to Armenia to fight Galerius ' force, to Narseh's disadvantage ; the rugged Armenian terrain was favorable to Roman infantry, but unfavorable to Sassanid cavalry.

Galerius continued moving down the Tigris, and took the Persian capital Ctesiphon before returning to Roman territory along the Euphrates.

Diocletian was conservative in matters of religion, a man faithful to the traditional Roman pantheon and understanding of demands for religious purification, but Eusebius, Lactantius and Constantine state that it was Galerius, not Diocletian, who was the prime supporter of the purge, and its greatest beneficiary.

* 293 – Roman Emperors Diocletian and Maximian appoint Galerius as Caesar to Diocletian, beginning the period of four rulers known as the Tetrarchy.

* 308 – At Carnuntum, Emperor emeritus Diocletian confers with Galerius, Augustus of the East, and Maximianus, the recently returned former Augustus of the West, in an attempt to restore order to the Roman Empire.

* Adrian of Nicomedia ( died 306 ), Herculian Guard of the Roman Emperor Galerius Maximian

After suffering a defeat by the Persians in 296, Galerius crushed Narseh in 298 — reversing a series of Roman defeats throughout the century — capturing members of the imperial household and a substantial amount of booty and gaining a highly favourable peace treaty, which secured peace between the two powers for a generation.

The first book sketches briefly the history of the early Roman emperors from Augustus to Diocletian ( 305 ); the second, third and fourth deal more fully with the period from the accession of Constantius Chlorus and Galerius to the death of Theodosius I ; the fifth and sixth, the most useful for historians, cover the period between 395 and 410, when Priscus Attalus was deposed ; for this period, he is the most important surviving non-ecclesiastical source.

* A number of Roman emperors of the 3rd-5th century were of Thraco-Roman backgrounds ( Maximinus Thrax, Licinius, Galerius, Aureolus, Leo the Thracian, etc .).

The 4th century AD Arch of Galerius and Rotunda | Rotunda of Galerius, one of several Roman monuments in the city and a UNESCO World Heritage Site.

When the Roman Empire was divided into the tetrarchy, Thessaloniki became the administrative capital of one of the four portions of the Empire under Galerius Maximianus Caesar, where Galerius commissioned an imperial palace, a new hippodrome, a triumphal arch and a mausoleum among others.

* Galerius, Roman Caesar in the Balkan, proves his worth in campaigning on the Danube frontier, fighting the Goths, Marcomanni, Sarmatians, and Carpi.

* Galerius is given the unspectacular job of land reclamation and repopulation, moving the entire tribe of the Carpi to settlements within the Roman Empire.

* Galerius, Roman Emperor ( approximate date )

* Gaius Galerius Valerius Maximianus, Roman Emperor ( d. 311 )

* Galerius grants Constantine I the title Caesar and elevates Severus II to co-emperor of the Western Roman Empire.

* May 5 – Emperor Galerius declares on his deathbed religious freedom and issues his Edict of Toleration, ending persecution of Christians in the Eastern part of the Roman Empire.

* May 5 – Gaius Galerius Valerius Maximianus, Roman emperor

* Emperor Jovian negotiates a disastrous peace with Persia, surrendering four of the five Roman provinces gained by Caesar Galerius in 298, and the cities Nisibis and Singara ( Mesopotamia ).

The city subsequently expanded for a century and a half, it became a significant political and economical centre, moreso — it became one of the first Roman cities where Christianity was recognized as an official religion ( Еmperor Galerius ).

* Sirmium ( modern Sremska Mitrovica ) in the Vojvodina region of modern Serbia, and near Belgrade, on the Danube border ) was the capital of Galerius, the eastern Caesar ; this was to become the Balkans-Danube prefecture Illyricum.

In the East, the arrangements between the Augustus Diocletian and his Caesar, Galerius, were much more flexible.

Their Caesares, Galerius and Constantius Chlorus, were both raised to the rank of Augustus, and two new Caesares were appointed: Maximinus ( Caesar to Galerius ) and Flavius Valerius Severus ( Caesar to Constantius ).

By 308 there were therefore no fewer than four claimants to the rank of Augustus ( Galerius, Constantine, Maximian and Maxentius ), and only one to that of Caesar ( Maximinus ).

In the East, Galerius remained Augustus and Maximinus remained his Caesar.

* Constantine is made a Caesar by Galerius and returns to Britain.

Caesar Galerius led the pagan movement against Christianity and arrived to bring up Diocletian against Christianity in the year 302: first Christian soldiers had to leave the army, later the Church's property was confiscated and Christian books were destroyed.

Diocletian, the eastern Augustus, in order to keep the balance of power in the imperium elevated Galerius as his Caesar, possibly on May 21, 293 at Philippopolis.

Although prior to 303 there appeared to be tacit agreement between the Tetrarchs that Constantius ’ s son, Constantine and Maximian ’ s son Maxentius were to be promoted to the rank of Caesar once Diocletian and Maximian had resigned the purple, by the end of 304 Galerius had convinced Diocletian ( who in turn convinced Maximian ) to appoint Galerius ’ s nominees Severus and Maximinus Daia as Caesars.

Constantine, disappointed in his hopes to become a Caesar, fled the court of Galerius after Constantius had asked Galerius to release his son as Constantius was ill. Constantine joined his father's court at the coast of Gaul, just as he was preparing to campaign in Britain.

When Constantius died in 306, his son Constantine was crowned emperor on July 25 and subsequently accepted by Galerius into the tetrarchy as Caesar.

Maxentius refrained from using the titles Augustus or Caesar at first and styled himself princeps invictus ( Undefeated Prince ), in the hope of obtaining recognition of his reign by the senior emperor Galerius.

He rose to become a senior officer in the Roman army, and as an old friend of Galerius, that emperor ordered that Severus be appointed Caesar of the Western Roman Empire, a post that he succeeded to on 1 May 305.

The point of the work is to describe the deaths of the persecutors of Christians: Nero, Domitian, Decius, Valerian, Aurelian, and the contemporaries of Lactantius himself, Diocletian, Maximian, Galerius, and Maximinus.

He is later executed ( or forced to commit suicide ) after Emperor Galerius unsuccessfully invades Italy.

* The mausoleum of Galerius in Salonica ( Greece ) is converted into a church.

Hierocles is said to have been the instigator of the fierce persecution of the Christians under Galerius.

Constantine I, age 26, is declared Augustus ( emperor ) by his troops and awaits recognition by Emperor Galerius.

After Emperor Galerius unsuccessfully invades Italy to suppress Maxentius, he is executed ( or forced to commit suicide ).

It is also possible that Galerius ' position at the head of the caravan was merely the conventional organization of an imperial progression, designed to show a Caesar's deference to his Augustus.

Early ( the exact date is unknown ) he married Valeria Maximilla, the daughter of Galerius.

It was expected that Maxentius would try the same strategy as against Severus and Galerius earlier ; that is, remaining in the well-defended city of Rome, and sit out a siege which would cost his enemy much more.

Following Galerius ' death, Maximinus was no longer constrained ; he enthusiastically took up renewed persecutions in the eastern territories under his control, encouraging petitions against Christians, one of which, addressed to him and to Constantine and Licinius, is preserved in a stone inscription at Arycanda in Lycia, " to request that the Christians, who have long been disloyal and still persist in the same mischievous intent, should at last be put down and not be suffered by any absurd novelty to offend against the honour due to the gods.

The Arch of Galerius, stands on what is now Egnatia & Dimitrios Gounari Street.

Artistic license was taken in the representations, for instance, the Caesar Galerius is shown in personal combat with the Sassanid Shah Narses in one of the panels ; although they never met in battle.

Galerius ' wife, Diocletian's daughter Valeria, is shown at his side, helping authenticate his connection to his predecessor.

Only Galerius is dressed in armor, and he makes the offering upon the altar.

The Rotunda of Galerius is 125m northeast of the Arch of Galerius at 40 ° 37 ' 59. 77 " N, 22 ° 57 ' 9. 77 " E. It is also known ( by its consecration and use ) as the Greek Orthodox Church of Agios Georgios, and is informally called the Church of the Rotunda ( or simply The Rotunda ).

Porphyry is also known as an opponent of Christianity and defender of Paganism ; his defense of traditional religion, Philosophy from Oracles, written before the persecutions of Christians under Diocletian and Galerius, set out the basis for them: