The ancient Roman port of Naustathmus has been identified with Ras al-Hillal (“Cape Crescent”) in Libya. When the emperor Justinian reorganized the southern border (in 538/539), he fortified several ports. Churches were built to make sure that the sailors and soldiers would always receive divine help. The church of Ras al-Hillal has survived pretty well; it must have been a very big building. After a century, the church was converted into a mosque.
Naustathmos (Ras al-Hillal)