Bygrave House

Description

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)

Comments

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.