The oval inner bailey and extant inner curtain wall date to the mid C12 and were built by Henry de Essex, Constable of England and Lord Warden of the Cinque Ports.
The curtain wall includes 3 round Norman towers which rather unusually project inwards. The most eastern tower was later incorporated into the grand barbican erected as part of the extensive remodelling undertaken by Archbishop William Courtenay in 1382. The Archbishop also added 2 projecting square towers to the southern section of the inner curtain and erected an outer curtain wall which is now ruinous.
Following C20 restoration the barbican remains inhabited. The moated inner bailey also contains 2 halls, again very unusual.
The oldest of the 2 dates from the early C14, based on the window tracery, and is now quite ruinous. The other, dates from the late C14 and was built as the Archbishop's audience chamber.
Now a largely modern reconstruction although the vaulted undercroft is original.