The picture above is a copy of the bottom right part of Thew’s ‘Plan of the Town of Kingston upon Hull, from an Actual Survey, 1784’ and shows the ‘Citadel’ near the east bank of the lower River Hull. The Citadel was a roughly triangular fortified enclosure and was built in the 1680s as an improvement on the Henrician line of defence built a century earlier (s.p.b.s). Within the curtain wall remained two of the three Henrician blockhouses, the northernmost one and its linking defensive wall being allowed to decay. The curtain wall of the Citadel was further defended by a moat on two sides with sluice gates connecting it to the Humber, while the south curtain wall section was built into the foreshore.
In 1681 the government’s Ordnance Commissioners required improvement in Hull’s defences with ‘all expedition according to proposals already presented’ (Gillett E. and MacMahon K.A. A History of Hull (University of Hull, 1980, 194). The engineer-in-charge, in Hull and elsewhere, was a Swedish soldier Martin Beckman and his deployment of multi-angular curtain walls was progressive for its day. The incentive for the building of the Citadel was an ongoing series of Dutch Wars spanning the years of the Commonwealth and Protectorate and the restored monarchy – Dutch warships might threaten any port on the coast of the North Sea.
At the top left of this extract from Thew’s plan/map may be seen some surviving elements of the gardens of Suffolk Palace – see the relevant article in the Articles/Publications section.