The table counted the years starting from the presumed birth of Christ, rather than the accession of the emperor Diocletian on 20 November 284, or as stated by Dionysius: " sed magis elegimus ab incarnatione Domini nostri Jesu Christi annorum tempora praenotare ..." It is assumed Dionysius Exiguus intended either 1 AD or 1 BC to be the year of Christ's birth ( a " year zero " does not exist in this calendar ).

Ar., lxiv, and De Syn., xviii ), St Athanasius does not recall from memory being a first hand witness to the onset of the great persecution by the Tetrarchy of Diocletian and Maximian in February 303, for in referring to the events of this period he makes no direct appeal to his own personal recollections, but falls back on tradition.

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.

Such numbers may have amounted to a substantial proportion, if not all, of the Peucini Bastarnae: Victor claims that the Carpi resettled in Pannonia by Diocletian at the same time, together with those previously transferred by Aurelian, amounted to the entire Carpi tribe.

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

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

Weakened by illness, Diocletian left the imperial office on 1 May 305, and became the only Roman emperor to voluntarily abdicate the position.

Diocletian dated his reign from his elevation by the army, not the date of his ratification by the Senate, following the practice established by Carus, who had declared the Senate's ratification a useless formality.

If Diocletian ever did enter Rome shortly after his accession, he did not stay long ; he is attested back in the Balkans by 2 November 285, on campaign against the Sarmatians.

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

They were joined by blood and marriage ; Diocletian and Maximian now styled themselves as brothers.

Domitianus died in December 297, by which time Diocletian had secured control of the Egyptian countryside.

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.

Diocletian believed that Romanus of Caesarea was arrogant, and he left the city for Nicomedia in the winter, accompanied by Galerius.

Rhetorically Eusebius records the Oracle as saying " The just on Earth ..." These impious, Diocletian was informed by members of the court, could only refer to the Christians of the Empire.

Diocletian was demonized by his Christian successors: Lactantius intimated that Diocletian's ascendancy heralded the apocalypse, and in Serbian mythology, Diocletian is remembered as Dukljan, the adversary of God.

Diocletian regulated his court by distinguishing separate departments ( scrina ) for different tasks.

These dukes sometimes administered two or three of the new provinces created by Diocletian, and had forces ranging from two thousand to more than twenty thousand men.

The Codex Gregorianus includes rescripts up to 292, which the Codex Hermogenianus updated with a comprehensive collection of rescripts issued by Diocletian in 293 and 294.

The fifth-century pagan Zosimus, by contrast, praised Diocletian for keeping troops on the borders, rather than keeping them in the cities, as Constantine was held to have done.

By the time of Diocletian, emperors were openly " monarchs ", but the contrast with " kings " was maintained: Although the imperial succession was, de facto, generally hereditary, it was only hereditary if there was a suitable candidate acceptable to the army and the bureaucracy so the principle of automatic inheritance was not adopted.

After Diocletian, however, Emperors started to wear jeweled robes and shoes, in contrast with the simple toga praetexta used by Principate Emperors in emulation of Augustus.

Diocletian, by contrast, was willing to reform every aspect of public life to satisfy his goals.

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

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.

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.

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.