At the conclusion of discussions with the Persians, Diocletian re-organized the Mesopotamian frontier and fortified the city of Circesium ( Buseire, Syria ) on the Euphrates.

In the late spring of 293-294 Diocletian journeyed through his realm and he re-organized Viminacium as capital of the new province of Moesia Superior Margensis.

Diocletian and the Tetrarchs had no consistent plan for frontier advancement, and records of raids and forts built across the frontier are likely to indicate only temporary claims.

Both these views had some truth to them, despite the biases of their authors: Diocletian and the Tetrarchs did greatly expand the army, and the growth was mostly in frontier regions, although it is difficult to establish the precise details of these shifts given the weakness of the sources.

Palace of the Roman Emperor Diocletian, around which the Croatian city of Split ( city ) | Split emerged.

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.

There is a contemporary issue of coins suggestive of an imperial adventus ( arrival ) for the city, but some modern historians state that Diocletian avoided the city, and that he did so on principle, as the city and its Senate were no longer politically relevant to the affairs of the Empire and needed to be taught as much.

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

Diocletian entered the city of Rome in the early winter of 303.

Diocletian soon grew impatient with the city, as the Romans acted towards him with what Edward Gibbon, following Lactantius, calls " licentious familiarity ".

In addition to his administrative and legal impact on history, the Emperor Diocletian is considered to be the founder of the city of Split in modern-day Croatia.

According to tradition, San Marino was founded in 301 AD when a Christian stonemason named Marinus the Dalmatian, later venerated as Saint Marinus, emigrated in 257 AD from the Dalmatian island of Rab, then a Roman colony, when the emperor Diocletian issued a decree calling for the reconstruction of the city walls of Rimini which had been destroyed by Liburnian pirates.

He was probably a Roman soldier martyred for the Christian faith during the persecution of Diocletian in 304 in the city of Porto Torres (), according to the legend on the orders of the governor ( preside ) of Sardinia and Corsica, a certain Barbarus.

Under the reorganization of the empire by Diocletian, Rouen became the chief city of the divided province of Gallia Lugdunensis II and reached the apogee of its Roman development, with an amphitheatre and thermae of which the foundations remain.

The Romans based much of their architecture on the dome, such as Hadrian's Pantheon in the city of Rome, the Baths of Diocletian and the Baths of Caracalla.

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.

An imperial palace was constructed here, in which the emperors after the time of Diocletian frequently resided ; and the city often played a part in the struggles between the rulers of the 4th century.

According to Koch, the name Arawn may be derived from the Biblical name Aaron, the name of Moses ’ s brother, and so is ultimately of Hebrew origin and meaning ‘ exalted .’ That the name ‘ Aaron ’ had currency in Wales as early as Roman times is shown by Gildas who wrote that ‘ Aaron and Iulianus were Christian martyrs at Urbs Legionis ( the ‘ city of the legion ,’ probably Caerllion-ar-Wysg ) in the time of the Emperor Diocletian .’ a cleric of the Old Welsh name Araun witnessed two charters of 860 preserved in the book of Llandaf.

" Constructed between 1497 and 1514, the Cathedral houses the remains of Saints Justus and Pastor, two Christian schoolboys martyred near the city during the persecutions of the Roman Emperor Diocletian at the beginning of the fourth century.

The Emperor Diocletian ( r. 284-305 ) was the last of the great builders of Rome's city infrastructure and he did not omit the Forum from his program.

Nicomedia was the metropolis of Bithynia under the Roman Empire, and Diocletian made it the eastern capital city of the Roman Empire in 286 when he introduced the Tetrarchy system.

This coat of arms originates from the Roman Emperor Diocletian who made his palace ( the core of city of Split ) the capital of the Western Roman Empire.

In the sixth century the city was renamed Georgiopolis after St. George, a soldier in the guard of the emperor Diocletian, who was born there between 256 and 285 AD.

Nicomedia was the eastern and most senior capital city of the Roman Empire between 286 and 324, during the Tetrarchy introduced by Diocletian.

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

Eusebius references to the encampment of the Legio X Fretensis at Aila ( in southern Israel, near modern Aqaba and Eilat ); the X Fretensis was probably transferred from Jerusalem to Aila under Diocletian.

Petrarch was moved to defend Celestine vigorously against the accusation of cowardice and some modern scholars ( e. g., Mark Musa ) have suggested Dante may have meant someone else ( Esau, Diocletian and Pontius Pilate have been variously suggested ).

The term Tetrarchy ( Greek: " leadership of four ") describes any form of government where power is divided among four individuals, but in modern usage usually refers to the system instituted by Roman Emperor Diocletian in 293, marking the end of the Crisis of the Third Century and the recovery of the Roman Empire.

* Nicomedia in northwestern Asia Minor ( modern Izmit in Turkey ), a base for defence against invasion from the Balkans and Persia's Sassanids was the capital of Diocletian, the eastern ( and most senior ) Augustus ; in the final reorganisation by Constantine the Great, in 318, the equivalent of his domain, facing the most redoubtable foreign enemy, Sassanid Persia, became the pretorian prefecture Oriens ' the East ', the core of later Byzantium.

* May 1 – Emperor Diocletian abdicates at age 60 and retires to his palace at Salona ( modern Split ) on the Adriatic coast after a reign of nearly 21 years in which the last vestiges of republican government have disappeared.

The district called Dardania ( in Upper Moesia ), was formed into a special province by Diocletian, with the capital at Naissus or Nissa ( modern Niš ).

They covered a period of 95 years or five decennovenal ( 19-year ) cycles with years dated in the Diocletian Era, whose first year was 285 ( the modern historical year in progress at Easter ).

In modern histories the destruction of the palace of Diocletian at Nicomedia has been described as a " fourth-century Reichstag fire " used to justify an extensive persecution of the Christians.

Significantly, neither Diocletian nor his co-emperor, Maximian, spent much time in Rome after 286, establishing their imperial capitals at Nicomedia and Mediolanum ( modern Milan ), respectively.

The first is that the Greek and Latin legends of Saint Christopher identify him as belonging to the Third Valerian Cohort of the Marmantae ( Latin: Cohors tertia Valeria, at Marmantarum ), a military unit of Northern Africa of Marmarica ( between modern day Libya and Egypt ), recruited by none other than the Emperor Diocletian.

When the Roman Emperor Diocletian retired, he erected a monumental palace nearby ; this massive structure, known as Diocletian's Palace, became the core of the modern city of Split.

The Dominate also featured a shift in the Empire's " center of gravity " from the west to the east, particularly after the establishment of Constantinople ; neither Diocletian nor his co-Emperor Maximian spent much time in Rome after 286, establishing their Imperial capitals at Nicomedia and Mediolanum ( modern Milan ), respectively.

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.

Art dating from the Diocletian period ( 286 – 305 AD ) in Villa Romana del Casale, Sicily depicts women in garments resembling bikinis in mosaics on the floor.

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

Diocletian delegated further on 1 March 293, appointing Galerius and Constantius as Caesars, junior co-emperors.

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

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.

The titles were probably meant to convey certain characteristics of their associated leaders ; Diocletian, in Jovian style, would take on the dominating roles of planning and commanding ; Maximian, in Herculian mode, would act as Jupiter's heroic subordinate.

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

By the end of his reign, Diocletian had secured the entire length of the Danube, provided it with forts, bridgeheads, highways, and walled towns, and sent fifteen or more legions to patrol the region ; an inscription at Sexaginta Prista on the Lower Danube extolled restored tranquilitas at the region.

Diocletian moved into Egypt to suppress him, first putting down rebels in the Thebaid in the autumn of 297, then moving on to besiege Alexandria.

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.

When Diocletian reappeared in public on 1 March 305, he was emaciated and barely recognizable.

Diocletian and Maximian were both present on 11 November 308, to see Galerius appoint Licinius to be Augustus in place of Severus, who had died at the hands of Maxentius.

Within his court Diocletian maintained a permanent body of legal advisers, men with significant influence on his re-ordering of juridical affairs.

On one occasion, Diocletian had to exhort a proconsul of Africa not to fear the consequences of treading on the toes of the local magnates of senatorial rank.

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.

Diocletian therefore issued his Edict on Coinage, an act re-tariffing all debts so that the nummi, the most common coin in circulation, would be worth half as much.

* Dioclesian, Henry Purcell's 1690 tragicomic semi-opera, loosely based on the life of the historical Diocletian

15 minute audio lecture on Diocletian.

The Principate ( 27 BC-284 AD ) period was succeeded by what is known as the Dominate ( 284 AD-527 AD ), during which Emperor Diocletian tried to put the Empire on a more formal footing.

A work on the martyrs of Palestine in the time of Diocletian was composed after 311 ; numerous fragments are scattered in legendaries which have yet to be collected.