Constantine I, also known as Constantine the Great, was a 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, decriminalizing Christian practice and ceasing Christian persecution in a period referred to as the Constantinian shift. This initiated the cessation of the established ancient Roman religion. Constantine is also the originator of the religiopolitical ideology known as Constantinism, which epitomizes the unity of church and state, as opposed to separation of church and state. He founded the city of Constantinople and made it the capital of the Empire, which remained so for over a millenium.
The Tetrarchy was the system instituted by Roman emperor Diocletian in 293 AD to govern the ancient Roman Empire by dividing it between two emperors, the augusti, and their junior colleagues and designated successors, the caesares.
Marcus Aurelius Claudius "Gothicus", also known as Claudius II, was Roman emperor from 268 to 270. During his reign he fought successfully against the Alemanni and decisively defeated the Goths at the Battle of Naissus. He died after succumbing to a "pestilence", possibly the Plague of Cyprian that had ravaged the provinces of the Empire.
Flavius Valerius Constantius, also called Constantius I, was a Roman emperor from 305 to 306. He was one of the four original members of the Tetrarchy established by Diocletian, first serving as caesar from 293 to 305 and then ruling as augustus until his death. Constantius was also father of Constantine the Great, the first Christian emperor of Rome. The nickname "Chlorus" was first popularized by Byzantine-era historians and not used during the emperor's lifetime.
Marcus Aurelius Probus was Roman emperor from 276 to 282. Probus was an active and successful general as well as a conscientious administrator, and in his reign of six years he secured prosperity for the inner provinces while withstanding repeated invasions of barbarian tribes on almost every sector of the frontier.
Valentinian I, sometimes called Valentinian the Great, was Roman emperor from 364 to 375. He ruled the Western half of the empire, while his brother Valens ruled the East. During his reign, he fought successfully against the Alamanni, Quadi, and Sarmatians, strengthening the border fortifications and conducting campaigns across the Rhine and Danube. His general Theodosius defeated a revolt in Africa and the Great Conspiracy, a coordinated assault on Roman Britain by Picts, Scoti, and Saxons. Valentinian founded the Valentinianic dynasty, with his sons Gratian and Valentinian II succeeding him in the western half of the empire.
Maximian, nicknamed Herculius, was Roman emperor from 286 to 305. He was Caesar from 285 to 286, then Augustus from 286 to 305. He shared the latter title with his co-emperor and superior, Diocletian, whose political brain complemented Maximian's military brawn. Maximian established his residence at Trier but spent most of his time on campaign. In late 285, he suppressed rebels in Gaul known as the Bagaudae. From 285 to 288, he fought against Germanic tribes along the Rhine frontier. Together with Diocletian, he launched a scorched earth campaign deep into Alamannic territory in 288, refortifying the frontier.
Gaius Messius Quintus Trajanus Decius, known as Trajan Decius or simply Decius, was Roman emperor from 249 to 251.
Sremska Mitrovica is a city and the administrative center of the Srem District in the autonomous province of Vojvodina, Serbia. It is situated on the left bank of the Sava river. As of 2022, the city has a total population of 40,144 inhabitants, while its administrative area has a population of 72,580 inhabitants.
Sirmium was a city in the Roman province of Pannonia, located on the Sava river, on the site of modern Sremska Mitrovica in the Vojvodina autonomous province of Serbia. First mentioned in the 4th century BC and originally inhabited by Illyrians and Celts, it was conquered by the Romans in the 1st century BC and subsequently became the capital of the Roman province of Pannonia Inferior. In 294 AD, Sirmium was proclaimed one of four capitals of the Roman Empire. It was also the capital of the Praetorian prefecture of Illyricum and of Pannonia Secunda. The site is protected as an archaeological Site of Exceptional Importance. The modern region of Syrmia was named after the city.
The Carpi or Carpiani were a Dacian tribe that resided in the eastern parts of modern Romania in the historical region of Moldavia from no later than c. AD 140 and until at least AD 318.
Illyricum was a Roman province that existed from 27 BC to sometime during the reign of Vespasian. The province comprised Illyria/Dalmatia in the south and Pannonia in the north. Illyria included the area along the east coast of the Adriatic Sea and its inland mountains, eventually being named Dalmatia. Pannonia included the northern plains that now are a part of Serbia, Croatia and Hungary. The area roughly corresponded to part or all of the territories of today's Albania, Kosovo, Montenegro, Serbia, Bosnia and Herzegovina, Croatia, and Slovenia.
The praetorian prefecture of Illyricum was one of four praetorian prefectures into which the Late Roman Empire was divided.
Illyro-Roman is a term used in historiography and anthropological studies for the Romanized Illyrians within the ancient Roman provinces of Illyricum, Moesia, Pannonia and Dardania.
Dalmatia was a Roman province. Its name is derived from the name of an Illyrian tribe called the Dalmatae, which lived in the central area of the eastern coast of the Adriatic Sea. It encompassed the northern part of present-day Albania, much of Croatia, Bosnia and Herzegovina, Montenegro, Kosovo and Serbia, thus covering an area significantly larger than the current Croatian region of Dalmatia. Originally this region was called Illyria or Illyricum.
Dardania was a Roman province in the Central Balkans, initially an unofficial region in Moesia (87–284), and then a province administratively part of the Diocese of Moesia (293–337). It was named after the tribe of the Dardani who inhabited the region in classical antiquity prior to the Roman conquest.
Much of the territory of the modern state of Serbia was part of the Roman Empire and later the Eastern Roman Empire. In particular, the region of Central Serbia was under Roman rule for about 800 years, starting from the 1st century BC, interrupted by the arrival of the Slavs into the Balkans during the 6th century, but continued after fall of the First Bulgarian Empire in the early 11th century and permanently ended with the rise of the Second Bulgarian Empire in the late 12th century. The territories were administratively divided into the provinces of Moesia, Pannonia and Dardania. Moesia Superior roughly corresponds to modern Serbia proper; Pannonia Inferior included the eastern part of Serbia proper; Dardania included the western part of Serbia proper. After its reconquest from the Bulgarians by Emperor Basil II in 1018, it was reorganized into the Theme of Bulgaria.
The Conference of Carnuntum was a military conference held on November 11, 308, in the city of Carnuntum, which at the time was located in the province of Pannonia Prima. It was convened by the Augustus in the East Galerius as a way to settle the dispute over the title of Augustus in the West, and consequently, to cease the ongoing conflicts since the previous year when he, and before that Severus II, invaded the Italy of Maxentius and Maximian. Present at the conference were Diocletian, who had been retired since 305, and his former colleague, Maximian.
The Battle of Brescia was a confrontation that took place during the summer of 312, between the Roman emperors Constantine the Great and Maxentius in the town of Brescia, in northern Italy. Maxentius declared war on Constantine on the grounds that he wanted to avenge the death of his father Maximian, who had committed suicide after being defeated by him. Constantine would respond with a massive invasion of Italy.
