In his Easter table the year 532 AD was equated with the regnal year 248 of Emperor Diocletian.

A further massive transfer of Bastarnae was carried out by emperor Diocletian ( ruled 284-305 ) after he and his colleague Galerius defeated a coalition of Bastarnae and Carpi in 299.

Dalmatia was the birthplace of the Roman Emperor Diocletian, who, upon retirement from Emperor in AD 305, built a large palace near Salona, out of which the city of Split later developed.

Diocletian (; c. 22 December 244 – 3 December 311 ), was a Roman Emperor from 284 to 305.

After the deaths of Carus and his son Numerian on campaign in Persia, Diocletian was proclaimed Emperor.

The title was also claimed by Carus ' other surviving son, Carinus, but Diocletian defeated him in the Battle of the Margus.

Diocletian was probably born near Salona in Dalmatia ( Solin in modern Croatia ), some time around 244.

He was a man skilled in areas of government where Diocletian, presumably, had no experience.

Diocletian was not the only challenger to Carinus ' rule: the usurper M. Aurelius Julianus, Carinus ' corrector Venetiae, took control of northern Italy and Pannonia after Diocletian's accession.

It was all good publicity for Diocletian, and it aided in his portrayal of Carinus as a cruel and oppressive tyrant.

As leader of the united East, Diocletian was clearly the greater threat.

It was too much for a single person to control, and Diocletian needed a lieutenant.

Diocletian was in a less comfortable position than most of his predecessors, as he had a daughter, Valeria, but no sons.

The relationship between Diocletian and Maximian was quickly couched in religious terms.

Diocletian refused and fought a battle with them, but was unable to secure a complete victory.

Bahram II's gifts were widely recognized as symbolic of a victory in the ongoing conflict with Persia ; Diocletian was hailed as the " founder of eternal peace ".

Maximian's appointment is unusual in that it was impossible for Diocletian to have been present to witness the event.

It has even been suggested that Maximian usurped the title, and was only later recognized by Diocletian in hopes of avoiding civil war.

On his return to the East, Diocletian managed what was probably another rapid campaign against the resurgent Sarmatians.

Afterwards, during 299 and 302, as Diocletian was then residing in the East, it was Galerius ' turn to campaign victoriously on the Danube.

In a public ceremony at Antioch, the official version of events was clear: Galerius was responsible for the defeat ; Diocletian was not.

It is unclear if Diocletian was present to assist the campaign ; he might have returned to Egypt or Syria.

Diocletian, acclaimed emperor on November 20, 284, was a religious conservative, faithful to the traditional Roman cult.

Diocletian took care of matters in the Eastern regions of the Empire while Maximian similarly took charge of the Western regions.

It presents itself as a compilation of works by six different authors ( collectively known as the Scriptores Historiae Augustae ), written in the reigns of Diocletian and Constantine I, but the true authorship of the work, its actual date, and its purpose, have long been matters for controversy.

Diocletian found much to be offended by in Manichean religion: its novelty, its alien origins, the way it corrupted the morals of the Roman race, and its inherent opposition to long-standing religious traditions.

Before Christianity became the official religion of the Roman Empire during the reign of the Emperor Constantine I, Diocletian and Maximian passed strict anti-polygamy laws in 285 that mandated monogamy was the only form of legal marital configuration, as had traditionally been the case in classical Greece and Rome themselves.

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:

Diocletian found much to be offended by in Manichean religion.

Christian tradition makes him a native of the Dalmatian city of Salona, today Solin near Split, the son of a man also named Caius, and a member of a noble family related to the Emperor Diocletian.

The background to the dog-headed Christopher is laid in the reign of the Emperor Diocletian, when a man named Reprebus, Rebrebus or Reprobus ( the " reprobate " or " scoundrel ") was captured in combat against tribes dwelling to the west of Egypt in Cyrenaica.

According to Sebastian's 5th-century Acta Sanctorum, still attributed to Ambrose by the 17th-century hagiographer Jean Bolland, and the briefer account in Legenda Aurea, he was a man of Gallia Narbonensis who was taught in Milan and appointed as a captain of the Praetorian Guard under Diocletian and Maximian, who were unaware that he was a Christian.

The biographies have Demetrius as a young man of senatorial family who was run through with spears in around 306 AD in Thessaloniki, during the Christian persecutions of the emperor Diocletian or Galerius, which matches his depiction in the 7th century mosaics.

The background to the dog-headed Christopher is laid in the reign of the Emperor Diocletian, when a man named Reprebus, Rebrebus or Reprobus ( the " reprobate " or " scoundrel ") was captured in combat against tribes dwelling to the west of Egypt in Cyrenaica.

Thus Diocletian, who ruled from Nicomedia, promoted two faithful legions from the Illyricum ( Legio V Iovia and VI Herculia ), the area he was also descended from, to be the personal protectors of the Roman Emperors.

Galerius, aided by Diocletian, campaigned successfully against Sassanid Persia, the Empire's traditional enemy.

On 1 May 305, Diocletian called an assembly of his generals, traditional companion troops, and representatives from distant legions.

The accession to the purple on 20 November 284, of Diocletian, the lower-class, Greek-speaking Dalmatian commander of Carus's and Numerian's household cavalry ( protectores domestici ), marked a major departure from traditional Roman constitutional theory regarding the emperor, who was nominally first among equals ; Diocletian introduced oriental despotism into the imperial dignity.

The accession on November 20, 284, of Diocletian, the lower-class, Greek-speaking Dalmatian commander of Carus's and Numerian's household cavalry, marked a major departure from traditional Roman constitutional theory regarding the Emperor, who was nominally first among equals during the Principate.

Diocletian, impressed with the boy's determination to resist, promised him wealth and power, but Pancras refused, and finally the emperor ordered him to be decapitated on the Via Aurelia, on May 12, 303 AD ; this traditional year of his martyrdom cannot be squared with the saint's defiance of Diocletian in Rome, which the emperor had not visited since 286, nor with the mention of Cornelius ( 251-253 ) as bishop of Rome at the time of the martyrdom, as the most recent monograph on Pancras's texts and cult has pointed out.

According to traditional hagiography, the saint served as a soldier in the Roman Army and was killed on the orders of the emperor Diocletian in 303 for refusing to persecute Christians and confessing to his own Christianity.

Rather than maintain the traditional infantry-heavy legions, Diocletian reformed it into limitanei (" border ") and comitatenses (" field ") units.

The persecution of Christians under Diocletian or other Roman Emperors usually furnished the background for soldier-saint hagiography which has a common theme: a soldier of the Empire who has become a Christian finds that his devotion conflicts with traditional religious practices of the Roman military.

In 303, the Emperors Diocletian, Maximian, Galerius and Constantius issued a series of edicts rescinding the legal rights of Christians and demanding that they comply with traditional Roman religious practices.