Portchester (Portus Adurni) Castle Fort – Quick Facts


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  • Saxon Shore Fort built in AD 280s – possibly by Marcus Aurelius Carausius, self-proclaimed emperor of Britannia and northern Gaul from AD 286-293.
  • Guarded harbour, first against an invasion by Roman Emperor then against raids by Saxons, Jutes and Angles from the continent.
  • After Roman withdrawal in the early fifth century, was home to a Saxon community.
  • Large Norman keep and castle built in the fort after AD 1066.
  • Became Royal residence of Richard II in AD 1390s.
  • Occupied until 17thcentury.
  • Prisoner-of-war camp until the end of the Napoleonic Wars.

What Remains

  • Most complete fort walls of any Roman fort in Europe. They enclose the entire fort area of 9 acres and stand at their original height, although upper level and parapets are medieval.
  • 16 of 20 regularly positioned D-shaped towers still stand along the walls.
  • Large Norman keep, moat and inner bailey occupies northwest quarter of fort.
  • Later Royal castle built by Richard II attached to Norman keep.
  • Medieval church of St. Mary and graveyard occupies southeast quarter of fort.