Question: Which empire was the Castellum of Godrici located?
Context: Blavia castellum was a military fort built by the Romans in the Aquitanian period of the Tractatus Armoricani, an ancient and literary name for the northwest part of France, especially Brittany.  The fort is referenced in the death of Charibert I.  History puts the fort in existence during the Merovingian empire in modern day France. The Roman fort at Weissenburg (German: "Kastell Weißenburg" ), called Biriciana in ancient times, is a former Roman Ala castellum, which is a UNESCO World Heritage Site located near the Upper Germanic-Rhaetian Limes.  It lies in the borough of Weißenburg in the Middle Franconian county of Weißenburg-Gunzenhausen in Germany.  Today the castellum is one of the most important sites of research in the Roman "limes" in Germany.  The site contains partly subterranean building remains, a reconstructed north gateway, large thermal baths and a Roman Museum with an integrated Limes Information Centre. Albaniana was the name of a Roman fort ("castellum") in modern-day Alphen aan den Rijn, Netherlands.  The Tabula Peutingeriana situates it in between the "castella" of Matilo and Nigrum Pullum.  It was part of the Lower Germanic Limes and separated the Roman empire from tribal country to the north. Praetorium Agrippinae was a Roman settlement in the province of Lower Germania, in the area of the Cananefates, located in modern-day Valkenburg, Netherlands.  It was an army encampment (Lat.: "castellum") on the Old Rhine (at the time the major branch of the river Rhine), on the northern border of the Roman Empire, the limes.  Praetorium Agrippinae is mentioned on the Tabula Peutingeriana between the "castella" of Matilo in the east and Lugdunum Batavorum to the west. Celemantia (or Kelemantia; the modern name of the site is Leányvár) was a Roman castellum and settlement on the territory of the present-day municipality Iža (Hun: "Izsa"), some 4 km to the east of Komárno in Slovakia.  It is the biggest known Roman castellum in present-day Slovakia.  It was a part of the Roman Limes, the frontier-zone of the Empire. Houten Castellum is a railway station located in Houten, Netherlands, which opened at 8 January 2001 and it is located on the Utrecht–Boxtel railway .  Originally it was the southern most point of the Houten - Houten Castellum tram line.  This temporary service closed at 14 December 2008.  The services are operated by Nederlandse Spoorwegen.  During this time the service was operated by a tram from Hannover on loan to Nederlandse Spoorwegen, operated by HTM.  After closure of the tram line due to construction of a new station and expanding of the railway to 4 tracks, the tram service was replaced by a bus service.  The new station opened at 12 December 2010, since then the bus service ceased.  All local trains call at Houten Castellum at the center platform along the inner tracks, while Intercity services and cargo trains use the outer tracks. Houten is a railway station located in Houten, Netherlands.  The station was opened on 1 November 1868 and is located on the Utrecht–Boxtel railway and the Houten - Houten Castellum tram line which closed on 14 December 2008.  The services are operated by Nederlandse Spoorwegen.  The station was closed between 1935 and 1982. Godric of Mappestone was an Anglo-Saxon "thane" and landowner mentioned in the Domesday Book of 1086 as a tenant of Howel in modern Herefordshire.  Godric is best known for the construction of the first timber version of Goodrich Castle, probably during the late 1080s, when it was originally known as "Castellum Godrici", or "the castle of Godric".  Victorian historians, however, believed the castle to date back further to the pre-Norman conquest days of King Canute, and the site may have been among a small number of Saxon fortifications along the Welsh border. Cnut the Great (Old Norse: "Knútr inn ríki"; c. 995 – 12 November 1035), also known as Canute - whose father was Sweyn Forkbeard (which gave him the patronym "Sweynsson", Old Norse: "Sveinsson") - was King of Denmark, England and Norway; together often referred to as the North Sea Empire.  With the deaths of his heirs within a decade of his own, and Norman conquest of England in 1066, this legacy was mostly forgotten.  He is popularly invoked in the context of the legend of "King Canute and the waves", which usually misrepresents him as a deluded monarch believing he has supernatural powers, contrary to the original legend which portrays a wise king who rebuked his courtiers for their fawning behaviour. The Château de Brest is a castle in Brest, Finistère, France.  The oldest monument in the town, it is located at the mouth of the river Penfeld at the heart of the roadstead of Brest, one of the largest roadsteads in the world.  From the Roman castellum to Vauban's citadel, the site has over 1700 years of history, holding right up to the present day its original role as a military fortress and a strategic location of the highest importance.  It is thus the oldest castle in the world still in use, and was classified as a monument historique on 21 March 1923 .
Answer: North Sea Empire