Cyrenaica is a historic land in eastern Libya that is a Roman province.
Although there is some confusion about the exact territory annexed by the Roman Empire, it is known that Cyrenaica was transformed into a Roman province in 78 BCE. together with Crete. In 20 BCE it became a senatorial province, as did the more prominent western Africa proconsularis, and unlike Egypt, which became the imperial domain of sui generis (under the special management of the governor, praefectus augustalis) in 30 BCE.
Reforms carried out (including the uprising of the tetrarchy) by Diocletian in 296 CE changed the administrative structure of the province. Cyrenaica was divided into two separate provinces: Libya Superior, containing Pentapolis with its capital at Vyrene, and Libya Inferior with the capital in Marmarica.
Both provinces belonged to the Egyptian diocese.
Western neighbour – Tripolitania, the largest detached part of the former Africa proconsularis, has become part of the African diocese.
After the earthquake in 365 CE, Cyrenaica’s capital was moved to Ptolemais. After the empire was split in 395 CE Cyrenaica became part of the Eastern Roman Empire, bordering the west with Tripolitania, already under the rule of the Vandals.