Pannonia was a province of the Roman Empire bounded on the north and east by the Danube, coterminous westward with Noricum and upper Italy, and southward with Dalmatia and upper Moesia. Pannonia was located in the territory of present-day western Hungary, eastern Austria, northern Croatia, north-western Serbia, northern Slovenia and northern Bosnia and Herzegovina.
Moesia was an ancient region and later Roman province situated in the Balkans south of the Danube River, which included most of the territory of modern-day Central Serbia, Kosovo, the north-eastern parts of Albania and the northern parts of North Macedonia, the whole of Northern Bulgaria, Romanian Dobruja and small parts of Southern Ukraine.
Sirmium was a city in the Roman province of Pannonia, located on the Sava river, on the site of modern Sremska Mitrovica in northern 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.
Pannonia Inferior, lit. Lower Pannonia, was a province of the Roman Empire. Its capital was Sirmium. It was one of the border provinces on the Danube. It was formed in the year 103 AD by Emperor Trajan who divided the former province of Pannonia into two parts: Pannonia Superior and Pannonia Inferior. The province included parts of present-day states of Hungary, Serbia, Croatia, and Bosnia and Herzegovina. The province was bordered to the east by a Sarmatian tribe—the Iazyges. Later, the Vandals appeared to the north-east.
The praetorian prefecture of Illyricum was one of four praetorian prefectures into which the Late Roman Empire was divided.
The praetorian prefecture was the largest administrative division of the late Roman Empire, above the mid-level dioceses and the low-level provinces. Praetorian prefectures originated in the reign of Constantine I, reaching their more or less final form in the last third of the 4th century and surviving until the 7th century, when the reforms of Heraclius diminished the prefecture's power, and the Muslim conquests forced the East Roman Empire to adopt the new theme system. Elements of the prefecture's administrative apparatus however are documented to have survived in the Byzantine Empire until the first half of the 9th century.
The Battle of Cibalae was fought in 316 between the two Roman emperors Constantine I and Licinius. The site of the battle near the town of Cibalae in the Roman province of Pannonia Secunda, was approximately 350 kilometers within the territory of Licinius. Constantine won a resounding victory, despite being outnumbered.
The Pannonia Valeria or simply Valeria, also known as Pannonia Ripensis, was one of the provinces of the Roman Empire. It was formed in the year 296, during the reign of emperor Diocletian, in a division of Pannonia Inferior. The capital of the province was Sopianae. Pannonia Valeria included parts of present-day Hungary and Croatia.
Pannonia Prima was an ancient Roman province. It was formed in the year 296, during the reign of Emperor Diocletian. Previously, it was a part of the province of Pannonia Superior, which, along with Pannonia Inferior, was gradually divided into four administrative units: Pannonia Prima, Pannonia Secunda, Valeria, and Savia. This transition was completed by the time of Constantine. According to the Notitia Dignitatum, Pannonia Prima was governed by a Praeses.
Pannonia Savia or simply Savia, also known as Pannonia Ripariensis, was a Late Roman province. It was formed in the year 295, during the tetrarchy reform of Roman emperor Diocletian, and assigned to the civil diocese of Pannonia, which was attached in the fourth century to the Praetorian prefecture of Illyricum, and later to the Praetorian prefecture of Italy.
The Diocese of Pannonia, from 395 known as the Diocese of Illyricum, was a diocese of the Late Roman Empire. The seat of the vicarius was Sirmium.
Pannonia was a Byzantine province, which existed in present-day Syrmia region of Serbia in the 6th century. Its capital was Sirmium.
The Diocese of Dacia was a diocese of the later Roman Empire, in the area of modern western Bulgaria, central Serbia, Montenegro, northern Albania and northern North Macedonia. It was subordinate to the Praetorian prefecture of Illyricum. Its capital was at Serdica.
Dardania was a Roman province in the Central Balkans, initially an unofficial region in Moesia (87–284), 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 East Roman or Byzantine Empire. In particular, the region of Central Serbia was under Roman rule for about 600 years, from the 1st century BC until the arrival of the Slavs into the Balkans during the 6th 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.
Archbishopric of Justiniana Prima was an Eastern Christian autonomous Archbishopric with see in the city of Justiniana Prima and jurisdiction over the Late Roman Diocese of Dacia in central parts of the Southeastern Europe.
Moesia Prima was a frontier province of the late Roman Empire, situated in the central parts of present-day Serbia, along the south bank of the Danube River. Provincial capital was Viminacium, near modern Kostolac in Serbia).
The German and Sarmatian campaigns of Constantine were fought by the Roman Emperor Constantine I against the neighbouring Germanic peoples, including the Franks, Alemanni and Goths, as well as the Sarmatian Iazyges, along the whole Roman northern defensive system to protect the empire's borders, between 306 and 336.
The timeline of Hungarian history lists the important historical events that took place in the territory of Hungary or are closely connected to the history of the country.
Serbia, 
Croatia, 
Bosnia and Herzegovina 
