In 429 vandals ravage much of our region, including Ceuta and Tangier. Subsequently, the city is rebuilt and was ruled from vandals to Byzantine and Visigothic the period of which is difficult to ascertain.
The Byzantine occupation of 534 A.C. was ordered by Emperor Justinian I and executed by General Belisario. During this time, we know that Septon is truly a city.
Administered by a tribune and with a contingent of three hundred soldiers and a small fleet, walls are built, a port is constructed, and houses and public buildings erected, including, as mentioned by sources, a church dedicated to the Mother of God.
After the loss of Carthage, in 698, the city entered a phase of pseudo-autonomy, although linked to Visigothic who ruled across the Strait. Its governor, Count D. Julian, would have to face the first great invasion from the South in 709.