Dunwich Castle was a motte and bailey castle raised in 1090 by the Norman conquerors to protect the harbour and important port. It was built on the orders of Robert Malet, Lord of Eye, and incoporated a Neolithic long barrow in to its construction, as was determined by excavations carried out in the 1880's. Folk memories still regard Castle Hill as a "fairy mound" containing treasure and is also supposed to be hollow.
In 1100 following the death of William Rufus, Robert Malet backed his younger brother Robert of Normandy against his other brother Henry. As he backed the losing side he was forced into exile. In 1101 the King appointed Stephen de la Falaise as castellam, but by 1143 the role had passed to the Bigod family. In 1173, Robert, Earl of Leicester landed in the Orwell Estuary near Ipswich with a huge Flemish army. Earl Hugh Bigod went over to the rebels and joined him, but the men of Dunwich refused to allow Bigod and Leicester access to the town. When they refused, Leicester had gallows errected and offered no quarter if they did not surrender immediately. Dunwich held out, so he ordered his army to cross the walls, ironically built by Bigod.
That day you would have seen burgesses, right valiant,
knights
Sally forth to the ramparts; each man knows his task;
Some to draw bows, others to hurl spears.
The strong help the weak to rest frequently.
Within the town there was not a wife or girl
Who did not carry a stone to the palisade for throwing.
Thus did the people of Dunwich defend themselves.
In the morning the rebel army departed and marched to Bury St Edmunds, where they were decisively defeated at the Battle of Fornham. Following the revolt of Hugh Bigod, the small motte and bailey castle was slighted, (destroyed) and it was never to be rebuilt, though the impressive earth mound Castle Hill still towers over the estuary and town, surmounted by a small wood and Grisham's Folly. Sir Thomas Wake-Grisham was a debauched C18th aristocrat who built the mock ruined tower. A friend of Wilkes, amd a political radical, he was a Member of Parliament for Dunwich from 1772 to 1783, and a minor member of the Hellfire Club. Interested in inventions he corresponded extensively with Benjamin Franklin, and was a firm advocate of American Independence.
Castle Hill was purchased by Dunwich Borough Council upon the death of the last of the Wake-Grisham's, Sir Thomas's great, great grandaughter Emily, in 1927. It then became Castle Hill Park. It is surrounded by a six foot high flint wall with an ornate wrought iron arched entrance. Set into the top of the arch is an electric lamp that casts eerie shadows into the park at night. Beneath the arch is a lockable 'kissing gate' and a small sign that says that the park is open from 9 till 7 Monday to Friday and 9 till 12 on Sunday. Mounted on a piece of slate set into the wall next to the entrance is a brass plaque, which has the following inscription:-
Castle Hill Park was purchased from the estate of Emily Wake-Grisham (1848-1927) by Dunwich Borough Council for the enjoyment of the people of Dunwich. It was opened on 12th March 1928 by the Hon. George Grayson, Mayor of Dunwich