Praetorian prefecture of Illyricum

Praetorian prefecture of Illyricum
Praefectura praetorio per Illyricum
Ἐπαρχότης Ἰλλυρικοῦ
Praet. prefecture of the Eastern Roman Empire
347–630s

The praetorian prefecture of Illyricum (375–379)
CapitalSirmium, later Thessalonica
Historical eraLate antiquity
• Established
347
• Loss of most of Illyricum to Slavic incursions
630s
Political subdivisionsDiocese of Macedonia
Diocese of Dacia
Diocese of Pannonia (until 379)

The praetorian prefecture of Illyricum (Latin: praefectura praetorio per Illyricum; Greek: ὑπαρχία τῶν πραιτωρίων τοῦ Ἰλλυρικοῦ, also termed the prefecture of Illyricum) was one of four praetorian prefectures into which the Late Roman Empire was divided.

The administrative center of the prefecture was Sirmium from 375 to 379, then Thessalonica. The prefecture took its name from the older province of Illyricum, which in turn was named after ancient Illyria. In its greatest expanse it encompassed Pannonia, Noricum, Crete, and most of the Balkan peninsula except for Thrace.