Wikipedia
Gariannonum
Gariannonum, or Gariannum, was a Saxon Shore fort in Norfolk, England. The Notitia Dignitatum, a Roman Army “order of battle” from about AD 400, lists nine forts of the Saxon Shore in south and east England, among which one was called Gariannonor. It has been much discussed over the years in terms of spelling (Gariannonum, Garianonum, Gariannum), purpose (whether it really was intended for defence against Saxon raids), and location (whether Burgh Castle or the Caister-on-Sea site).