Henry I (1100-1135) gave £56 arising out of the Royal Manor of Leighton to the Abbey of Fontevrault in Anjou in 1129. In 1164 Henry II (1154-1189) granted the whole of the Royal Manor to the Abbey. The royal manorial buildings may have lain at Grovebury or elsewhere; but it is certain that the manorial buildings were at Grovebury following the building of Grove Priory.
The creation of Grove Priory and its attendant manorial lands seems to have been at the expense of Billington, then still a hamlet in the ancient parish of Leighton, to judge by the modern parish boundaries which do not follow geographical features but are, instead zig-zag suggestive of having been formed around the boundaries of enclosed fields. Grove Priory, despite the name, seems to have owned no land in the parish of Grove in Buckinghamshire and lay wholly within Bedfordshire, in an area of modern sand quarrying south of the A505 and Grovebury Farm.
The old royal manor as well as the priory attracted royal visits to Leighton. Queen Eleanor, wife of Henry III (1216-1272), and Mary of Woodstock, daughter of Edward I (1272-1307) were nuns at Amesbury Priory, the main religious house in England owned by Fontevrault after 1275. Mary was Lady of the Manor of Leighton alias Grovebury from before 1305 until her death in 1332 when Fontevrault's manor at Grove was taken into royal hands due to wars with France.
Henry III was in Leighton in 1264, Edward I in 1274, 1275, 1280 and 1290, Edward II in 1308, 1309, 1310 and 1316 and Edward III (1327-1377) in 1337 as entries in the Fine, Close and Patent Rolls held in The National Archives show. The kings may have always stayed at the manorial complex at Grove Priory or in the town, or both, it is impossible to say which, perhaps a clue comes from the fact that it is known that Edward I was in Leighton on the 1st and 2nd August 1290 and that his Chancellor, Robert Burnell, Bishop of Bath and Wells was at Grove on 31st July. Similarly in 1309 Edward II was definitely at Grove as a Calendar of Chancery Warrants 1244-1326 page 30 shows: "Mandate to let Gaston, Count of Foiz, have the letters required by the businesses contained in the schedule enclosed, which were shown before the king in the chancellor's presence at la Grove", the chancellor was John Langton, Bishop of Chichester. The royal visits were usually part of a progress and would have been either preceded or succeeded by visit to King's Langley in Hertfordshire.
Volume 8 published by Bedfordshire Historical Records Society in 1924 includes a transcription and translation of documents held at The National Archives about Grovebury Manor by Robert Richmond. One of these dates to about 1318 and gives the extent of the Manor under the lordship of Mary of Woodstock:
"The Manor of Grove. Six carucates [a carucate was the equivalent of a hide] of land are there, besides the ploughlands of the customary tenants which amount to [?one] carucate or more in demesne within the parish of Leighton. Assessed rent there is worth £60 yearly. Heuepanes, Giuepanes and Saint Peter's Pence [taxes] are worth yearly £6. The Farm of the Market [i.e. the lease of right to collect dues] is worth yearly £8. Perquisites of Court on the score of fines are worth £40 in ordinary years. There are in the Manor two water mills in one building, whereof one serves for corn and one for malting barley; and there is a windmill, with soke [a duty for using the mill] to the said mill. Meadow and pasture which are sold are worth yearly 20 marks [a mark was two thirds of a pound]. Wood is worth much yearly for pannage and underwood [the right to turn pigs out into the woodland]. On the Manor can be carried 8 cart horses, 20 affers, 60 oxen, four score cows, 200 lesser stock, 4,500 sheep, 200 swine".
"There is a certain Manor of Clipstone within the bounds of the parish of Leighton, belonging to the said Manor of Grove, with two and a half carucates of land; they are worth yearly £13".
"There is a certain Manor of Reach within the bounds of the same parish, belonging to the said Manor of Grove, with two and a half carucates of land, and they are worth yearly £13".
"There is a certain Manor of Stewkley [Buckinghamshire], outside the parish, belonging to the Manor of Grove, with three carucates of land and with wood; it is worth yearly £30".
"There is a certain Manor of Studham near Dunstable, outside the parish, with two carucates of land, one wind mill, and wood; it is worth yearly £8".
"There is a certain Manor in Northall [Buckinghamshire] near the parish of Leighton, with one carucate of land and one water mill; it is worth yearly £6".
"There are tenants in Radnage [Buckinghamshire] who render £4 of assessed rent at Grove, and there the manor holds a fair wood".
"And for the whole Henry the Bailiff renders to the Abbess of Fontevrault yearly eight score and ten pounds on account of all the Manors above written and for the manor [?of Grove] which the Lady "Mar'et'a" [Mary of Woodstock] holds to herself into her own hand as appears below".
"And besides this the Lady Mar'et'a has in her hand divers other Manors to the value of £100 and she receives this clear, to herself, and the said Henry is charged for payment of the whole rent as above".
"The extent of your Prebend of Leighton Buzzard is at 143½ marks, and the Abbot of Eynsham is Collector of the Tenth".
During the Hundred Years War the manor was often taken back into Crown ownership due to the conflict with France, being handed back to Fontevrault in the fleeting times of peace. Another document translated by Robert Richmond in 1924 was the Bailiff's accounts for the Manor from Michaelmas 1341 to Michaelmas 1342. These are very extensive and detailed.
Grove Priory and its associated manorial buildings were excavated from 1973 to 1985 by Bedfordshire County Council archaeology unit under Evelyn Baker. These excavations revealed much rebuilding at the site in the 14th century including tile ovens, timber buildings, drains and a rectangular well relating to a cobbled courtyard subdivided into terraced yards. The bailiff's accounts mentioned above record a pigeoncote, also identified by excavation, two new farm buildings, a cow house and "hakhous" which were built of wattle, daub and thatch. A stable, dairy and grain barn are also mentioned.
In 1413, when the manor was again owned by the Crown, it was granted to Sir John Phelip whose wife, Alice, was a grand-daughter of the poet and diplomat Geoffrey Chaucer. He was given permission to try and purchase the manor from Fontevrault and in 1414 he enfeoffed Thomas Chaucer with the manor but regained it the following year, when he died. His widow Alice married then William de la Pole, Duke of Suffolk and in 1444 the couple granted the reversion of the Manor to Eton College. Suffolk, a favourite of Henry VI (1421-1461 and 1470-1471) was murdered in 1450. After a dispute with the Crown about the ownership of the manor, Alice obtained a grant from the Crown of the manor to herself and her heirs in 1472. When she died in 1475 it passed to her son John, Duke of Suffolk, brother-in-law of King Edward IV (1471-1483) who alienated it to the Dean and Canons of Saint George's Chapel, Windsor in 1480. Edward IV had begun construction of the chapel in 1475.