Moesia Superior in the context of "Constantine I"

Constantine I (27 February 272 – 22 May 337), also known as Constantine the Great, or known mononymously as Constantine, was 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, the Edict of Milan decriminalising Christian practice and ceasing Christian persecution. This was a turning point in the Christianisation of the Roman Empire. He founded the city of Constantinople (now Istanbul) and made it the capital of the Empire, which it remained for over a millennium.

Born in Naissus, a city located in the province of Moesia Superior (now Niš, Serbia), Constantine was the son of Flavius Constantius, a Roman army officer from Moesia Superior, who would become one of the four emperors of the Tetrarchy. His mother, Helena, was a woman of low birth, probably from Bithynia. Later canonised as a saint, she is credited for the conversion of her son in some traditions, though others believe that Constantine converted her. He served with distinction under emperors Diocletian and Galerius. He began his career by campaigning in the eastern provinces against the Persians, before being recalled to the west in AD 305 to fight with his father in the province of Britannia. After his father's death in 306, Constantine was proclaimed as augustus (emperor) by his army at Eboracum (York, England). He eventually emerged victorious in Civil wars of the Tetrarchy against the emperors Maxentius and Licinius to become the sole ruler of the Roman Empire by 324.

In Roman literature of the early 1st century CE, the Moesi (/ˈmiːsaɪ/ or /ˈmiːzaɪ/; Ancient Greek: Μοισοί, Moisoí or Μυσοί, Mysoí; Latin: Moesi or Moesae) appear as a tribe who lived in the region around the Timok River to the south of the Danube. The Moesi do not appear in ancient sources before Augustus's death in 14 CE and are mentioned only by three authors dealing with the Roman warfare in the region and the ethnonymic situation between mid-1st century BC and mid-1st century CE: Ovid, Strabo and Livy. A Paleo-Balkan tribe known as the Moesi never actually existed in the Danube area before that period, it was a Roman invention. The ethnonym was transplanted from Asia Minor Mysians to the Balkans by the Romans as a replacement of the name of the Dardani who lived in the territory that later became the province of Moesia Superior. This decision in Roman literature is linked to the appropriation of the name Dardani in official Roman ideological discourse as Trojan ancestors of the Romans and the creation of a fictive name for the actual Dardani who were seen as barbarians and antagonists of Rome in antiquity. This new fictive Augustan terminology was illogically and controversially argumented by Strabo as the result of Aelius Catus's displacement of 50,000 Getae from the north to the south of the Danube, who settled areas in the north-eastern parts of the later province of Moesia Superior, thereafter being called "Moesi".

The Latin name Moesia was given first to the province of Moesia Superior and expanded into Moesia Inferior along the Danube. After the recreation of Dardania, Moesia referred to Moesia Prima, the northern part of Moesia Superior. A civitas of the Moesi which was reorganized as a Roman colony was located around Ratiaria in the first century AD.

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 (with interruptions), 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 (later Moesia Superior), Pannonia (later Pannonia Inferior) 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 Danube River influenced the extension of the Roman Empire; its confluents, such as Sava and Morava, affected the growth of frontier fortresses and towns. Many authors and explorers wrote about traces of the Roman Empire on the Danube coast. One of the localities, Felix Romuliana, was ranked on the list of cultural heritage of UNESCO in July 2007.

Legio VII Claudia (Latin for "The 7th Claudian Legion") was a legion of the Ancient Roman army.

Viminacium (also Viminatium) was a major city, military camp, and the capital of the Roman province of Moesia (modern Serbia). Following the division of Moesia in 87, following Domitian's Dacian War, it became the capital of Moesia Superior. As of 2018, only 3-4% of the site has been explored.

The site is located 6 km (3.7 mi) from the modern town of Kostolac in Eastern Serbia. The city dates back to the 1st century AD, and at its peak it is believed to have had 40,000 inhabitants, making it one of the biggest cities in the Balkans of that time. It lies on the Roman road Via Militaris. Viminacium was devastated by Huns in the 5th century, but was later rebuilt by Justinian. It was completely destroyed with the arrival of Slavs in the 6th century. Today, the archaeological site occupies a total of 450 hectares (1,100 acres), and contains remains of temples, streets, squares, amphitheatres, palaces, hippodromes and Roman baths.

Dacia Aureliana was a province in the eastern half of the Roman Empire established by Roman Emperor Aurelian in the territory of former Moesia Superior after his evacuation of Dacia Traiana beyond the Danube in 271. Between 271/275 and 285, it occupied most of what is today northwestern Bulgaria and eastern Serbia. Its capital was in Serdica (modern Sofia).

This province was populated with a part of the former inhabitants of Dacia Traiana. It is written in Eutropius' work: Abridgment of Roman History (9:15):

Legio IV Flavia Felix ("Lucky Flavian Fourth Legion") was a legion of the Imperial Roman army founded in AD 70 by the emperor Vespasian (r. 69–79) from the cadre of the disbanded Legio IV Macedonica. The legion was active in Moesia Superior in the first half of the 5th century. The legion symbol was a lion.