The comprehensive gazetteer and bibliography of the medieval castles, fortifications and palaces of England, Wales, the Islands.
The listings
Other Info
Print Page 
Next Record 
Previous Record 
Back to list 

Bygrave House

In the civil parish of Bygrave.
In the historic county of Hertfordshire.
Modern Authority of Hertfordshire.
1974 county of Hertfordshire.
Medieval County of Hertfordshire.

OS Map Grid Reference: TL26573610
Latitude 52.00891° Longitude -0.15732°

Bygrave House has been described as a probable Fortified Manor House, and also as a Palace but is rejected as such.

There are earthwork remains.


The site of a manor house apparently owned by one of the Bishops of Chester, hence the description "palace". The earthworks consist of an inner and surrounding enclosures defended by ditches along with an innermost square enclosure. The NW angle and much of the N side have been altered by the construction of a modern house and garden. (ONBs destroyed) (Andrews; RCHME).
"There was probably a mansion or manor house at Bygrave at an early date. Possibly it was at the house that Edward I stopped on his way to St Albans in January 1299 and April 1302." (There is no evidence in the manorial history of Bygrave to suggest it ever belonged to a Bishop of Chester) (VCH).
No trace of the palace, and no further information about it and it is not shown on the Enclosure Map (1808). The published site lies beneath the lawns of a modern house.
There is considerable doubt that the two broad ditches, now mainly dry, which occur around the palace site are in fact moats. The difference in height on the outer ditch between TL 2663 3611 and TL 2651 3604 is about 5.0m, therefore it cannot have held standing water. In places it is only about 6.0m wide and 0.8m deep; hardly a protection or a defence.
The inner ditch forming two sides of a square which was once an ornamental garden, may well have been associated with the garden. It is circa 8.0m wide and up to 1.8m deep. From the N extremity of the E arm (at TL 2661 3608) the ground slopes down to the church and it is impossible that a wet moat around the 'palace' could have existed (F1 NKB 16-MAR-73).
"Pentagonal ditched enclosure round a square moat immediately south of the parish church... To the west is a triangular ditched area which, with a larger rectangular one to the east, makes the whole complex a 'double square'. John de Thornebury had licence to crenellate two houses at Bygrave in 1386." (Renn). (PastScape)

Pentagonal ditched enclosure round a square moat (Renn). Polygonal outer ditch or moat (perhaps 7 or 8 sides originally) surrounding two surviving sides of what must have been a square enclosure. The latter now has a interior containing a house in different ownership. Inner moat 10-15m across and full of water; outer variable being encroached by ploughing on E where only small ditch 2-3 m across. Some enlargement by owner on SW. Adjoins church and so presumably a manor site (MWT (HCC) site visit. 10.3.1987). (Hertfordshire HER)

A Royal licence to crenellate was granted in 1386 Oct 31 (Click on the date for details of this licence.).


Moated work of considerable size licensed 1386 to Sir John Thornbury, a soldier with long experience as a mercenary in Europe. The licence was for 'two houses within his manor'.
This is a large and high status site. Some work is likely to have been built by a Thornbury, a man who defined himself by his military career, so was likely to have had some level of fortification, but the size and layout of the earthworks do not suggest serious fortification of castle like quality. However there was a manor here, mainly held by the Somery family, before then which may also have had some defences. The unusual size and quality of this moat is shown from it developing a story of being a bishop's palace, although that is not true.
Links to archaeological and architectural databases, mapping and other online resources

Data >
PastScape   County HER            
Maps >
Streetmap   NLS maps   Where's the path   Old-Maps      
Data/Maps > 
Magic   V. O. B.   Geology   LiDAR   Open Domesday  
Air Photos > 
Bing Maps   Google Maps   Getmapping   ZoomEarth      
Photos >
CastleFacts   Geograph   Flickr   Panoramio      

Sources of information, references and further reading
Most of the sites or buildings recorded in this web site are NOT open to the public and permission to visit a site must always be sought from the landowner or tenant.
It is an offence to disturb a Scheduled Monument without consent. It is a destruction of everyone's heritage to remove archaeological evidence from ANY site without proper recording and reporting.
Don't use metal detectors on historic sites without authorisation.
The information on this web page may be derived from information compiled by and/or copyright of Historic England, County Historic Environment Records and other individuals and organisations. It may also contain information licensed under the Open Government Licence. All the sources given should be consulted to identify the original copyright holder and permission obtained from them before use of the information on this site for commercial purposes.
The author and compiler of Gatehouse does not receive any income from the site and funds it himself. The information within this site is provided freely for educational purposes only.
The bibliography owes much to various bibliographies produced by John Kenyon for the Council for British Archaeology, the Castle Studies Group and others.
Suggestions for finding online and/or hard copies of bibliographical sources can be seen at this link.
Minor archaeological investigations, such as watching brief reports, and some other 'grey' literature is most likely to be held by H.E.R.s but is often poorly referenced and is unlikely to be recorded here, or elsewhere, but some suggestions can be found here.
The possible site or monument is represented on maps as a point location. This is a guide only. It should be noted that OS grid references defines an area, not a point location. In practice this means the actual center of the site or monument may often, but not always, be to the North East of the point shown. Locations derived from OS grid references and from latitude longitiude may differ by a small distance.
Further information on mapping and location can be seen at this link.
Please help to make this as useful a resource as possible by contacting Gatehouse if you see errors, can add information or have suggestions for improvements in functality and design.
Help is acknowledged.
This record last updated 26/07/2017 09:21:01

Home | Books | Links | Fortifications and Castles | Other Information | Help | Downloads | Author Information | Contact