Sandgate Castle was one of Henry VIII’s Device Forts. Built in 1539 near Sandgate, Kent, its exposed location has led to much damage by storm tides. Converted to a Martello Tower in the early 1800s, it is now in private ownership, open by arrangement with the Castle Gallery antique shop.
SANDGATE is another of the block-house forts built by Henry VIII., on the site, as is supposed, of a more ancient edifice. It is much on the same plan as the forts of Sandown and Walmer, but has been entirely altered on the seaward face, and now is somewhat in the shape of an ace of clubs, the double bastions being actually in the street of the town, and the front one projecting below high water line. This part was converted into one of the .Martello towers, erected by William Pitt, in 1806, during the French War, to protect all assailable points on the line of the S.E. coast where a landing might be effected.
The previous castle was one existing temp. Richard 11., who, in 1398, after he had banished his cousin, Henry of Bolingbroke, at the lists of Coventry for ten years (see BAGINTON, WARWICK), wrote letters to the captain of his castle of Sandgate, commanding him to admit his kinsman, Henry of Lancaster, Duke of Hereford, with his family, horses and attendants, to tarry there for six weeks to refresh himself. This must have been on Bolingbroke’s journey into banishment abroad, whence he returned within a year, to depose Richard and fill the throne himself. In 1588 Elizabeth lodged in this fort when making her progress through Kent to inspect the defences adopted against the projected Spanish invasion.(Castles Of England, Sir James D. Mackenzie, 1896)