Gaius Imperator Flavius is the Curator of Province of Illyricum.

Illyricum was the Roman province established in place of the former kingdom of Illyria. It stretched from the Drilon river in modern Albania to Istria (Slovenia/Croatia) in the north and the Sava river (Bosnia/Croatia) in the east. Its capital was located at Salonae near modern Split in Croatia.

The kingdom of Illyria was conquered in 168 BC, when the Romans defeated the army of the Illyrian king Gentius. From 167 BC, southern Illyria became a formally independent Roman protectorate.

The region had considerable strategic and economic importance for the Romans. It possessed a number of important commercial ports along its coastline, and had gold mines in its interior regions. Illyria was also the starting point of the Via Egnatia, the great Roman road that ran from Dyrrachium (modern Durazzo), on the Adriatic, to Byzantium in the east.

In 59 BC, after the Lex Vatinia, Illyricum was assigned as provincia together with Cisalpine Gaul (zone of responsibility rather than the province as is understood today) to Caesar. No province was established until Octavian's wars in Illyricum 35-33 BC and first mention of province Illyricum is in the context of Augustan settlement of 27 BC.

The province of Illyricum was subsequently enlarged as the Romans expanded their power in the region through a series of wars known as Pannonian wars (Bellum Pannonicum) 12-9 BC fought against group of peoples known as the Pannonians. Subsequent to 10 (some scholars as Jeno Fitz move this date to middle-late Claudian era c. 20-35), after a revolt of Pannonians and Dalmatians known a rebellion of Bato (Bellum Batonianum, 6-9) was crushed in 9, the province of Illyricum was dissolved, and its lands were divided between the new provinces of Pannonia in the north and Dalmatia in the south. The name continued to be used to refer to the region and was later applied by the emperor Diocletian to the Praetorian prefecture of Illyricum, one of four prefectures that he established, which encompassed Pannonia, Noricum, Crete, and the whole Balkan peninsula except Thrace.

The region's native peoples were renowned for their military prowess and they became an important source of manpower for the Roman army. Several notable Roman emperors came from the region, including Aurelian, Claudius II, Constantine I and Diocletian as well as the Byzantine emperors Anastasius I, Justinian I.

Physically, Spalatum resembles any typical large Roman colony. At its center was a forum, where people handled their legal and commercial affairs. In the northwest corner of the city was an amphitheater, which could seat 15,000, and also formed part of the town's fortifications. The entire city was surrounded by a wall, which were upgraded several times during the Roman occupation. As would be expected from a Roman city of its size, Salona had two major temples, baths, shops, and houses within its walls. The aqueducts that brought water to the city and the palace still serve Split today. Salona measured 1600 meters long by 700 meters wide.

Occupying 28,900 square meters, Diocletian's palace combined aspects of a fortress, a palace and a villa. Although the structure is commony called Diocletian's palace, Diocletian never lived there during his reign as Emperor. Thus, his palace could more accurately be called a luxury retirement home. Its strong walls and many towers give the palace the look of a military stronghold, and indeed, a large number of soldiers could be housed there. However, the palace never came under serious attack while it was under Roman control. Diocletian's palace was roughly square, with a gate in the middle of three of the walls, and towers on each of the corners. The sea came all the way up to the south side of the palace, and there was consequently no need for a gate on that wall. The northern half of the palace served as a barracks and servants quarters, while the imperial apartments were located on the south side. Between these two areas was the peristyle, where Diocletian performed any official duties he still retained. The Emperor's mausoleum was located just to the east of the peristyle.