§ 1. On the death of Constantius Chlorus (a.d. 306) the Roman army at Caer Efrog (York) hailed Constantine, his eldest son, Augustus and Emperor. Galerius, however, only ratified this election in part, allowing him to assume the sovereignty of the Western provinces with the title of Cæsar and the fourth degree of imperial rank. In the following year, Constantine acquired, by an agreement with Maximian, the title of Augustus; and after the victory which he gained near Rome over the Emperor Maxentius (a.d. 312), he openly avowed himself a Christian convert.

Constantine adopted Diocletian's division of the civil government of the empire into four præfectures, one of the East, one of Illyricum, one of Italy, and one of Gaul. Britain was included in the latter, and governed by a proprætor, who appears to have resided in the province henceforth called the Britannia Prima. Under him were two consular deputies, who appear to have respectively ruled and resided in the provinces henceforth severally known as the Britannia Secunda and the Maxima Cæsariensis. Three presidents, one in each province, were the appointed judges of civil and criminal causes. The finances of the island were administered by a receiver-general, who acted under the count of the imperial treasury.