Dunstanburgh Castle is a 14th-century fortification on the coast of Northumberland in northern England, between the villages of Craster and Embleton. The castle was built by Earl Thomas of Lancaster between 1313 and 1322. The curtain walls enclose 9.96 acres, making it the largest castle in Northumberland. The most prominent part of the castle is the Great Gatehouse, a massive three-storey fortification, considered by historians Alastair Oswald and Jeremy Ashbee to be "one of the most imposing structures in any English castle"
NU2521 : Great Keep - Dunstanburgh Castle The Great Gatehouse of Dunstanburgh, begun in 1313 by Thomas of Lancaster, had its passageway walled up in 1380 when John of Gaunt built his gatehouse to the northwest. The great gatehouse with its distinctive twin D-shape towers, was then used as a keep.