Robert d'Oilly, Baron of Hook Norton

http://en.wikipedia.org/wiki/Robert_D%27Oyly_%28Osney%29

11 Baron of Hook Norton, High Sheriff of Oxfordshire, ordered the building of Oxford Castle. Doomsday Book records that by 1086 he held a number of manors.

merged profile held place of death as Eynsham

entry for Hook Norton:
Hundred: Shipton
County: Oxfordshire
Total population: 84 households - very large.
Total tax assessed: 30 geld units - very large.
Taxable units: Taxable value 30 geld units.
Value: Value to lord in 1066 £30. Value to lord in 1086 £30. Value to lord c. 1070 £30.
Households: 76 villagers. 3 smallholders. 5 slaves.
Ploughland: land for 30 ploughlands. 5 lord's plough teams. 30 men's plough teams.
Other resources: 5.0 lord's lands. Meadow 140 acres. Pasture 5 * 2 furlongs. Woodland 2 * 0.5 furlongs. 2 mills, value 1.0.
Lord in 1066: brothers, three.
Lord in 1086: Robert d'Oilly.
Tenant-in-chief in 1086: Robert d'Oilly.
Phillimore reference: 28,6

excerpt from https://en.wikipedia.org/wiki/Oxford_Castle

According to the Abingdon Chronicle, Oxford Castle was built by the Norman baron Robert D'Oyly the elder from 1071-73. D'Oyly had arrived in England with William I in the Norman Conquest of England in 1066 and William the Conqueror granted him extensive lands in Oxfordshire. Oxford had been stormed in the invasion with considerable damage, and William directed D'Oyly to build a castle to dominate the town. In due course D'Oyly became the foremost landowner in Oxfordshire and was confirmed with a hereditary royal constableship for Oxford Castle. Oxford Castle is not among the 48 recorded in the Domesday Book of 1086, but not every castle in existence at the time was recorded in the survey.

D'Oyly positioned his castle to the west side of the town, using the natural protection of a stream of the River Thames on the far side of the castle, now called Castle Mill Stream, and diverting the stream to produce a moat. There has been debate as to whether there was an earlier English fortification on the site, but whilst there is archaeological evidence of earlier Anglo-Saxon habitation there is no conclusive evidence of fortification. Oxford Castle was clearly an "urban castle" but it remains uncertain whether local buildings had to be demolished to make room for it. The Domesday Book does not record any demolition, so the land may have already been empty due to the damage caused by the Norman seizure of the town. Alternatively the castle may have been imposed over an existing street front which would have required the demolition of at least several houses.

The initial castle was probably a large motte and bailey, copying the plan of the castle that D'Oyly had already built 12 miles away at Wallingford. The motte was originally about 60 feet high and 40 feet wide, constructed like the bailey from layers of gravel and strengthened with clay facing. There has been debate over the sequencing of the motte and the bailey: it has been suggested that the bailey may have built first, which would make the initial castle design a ringwork rather than a motte and bailey.

https://en.wikipedia.org/wiki/Motte-and-bailey_castle
A motte-and-bailey castle is a fortification with a wooden or stone keep situated on a raised earthwork called a motte, accompanied by an enclosed courtyard, or bailey, surrounded by a protective ditch and palisade.

By the mid-12th century Oxford Castle had been significantly extended in stone. The first such work was St George's Tower, built of coral rag stone in 1074, 30 by 30 feet at the base and tapering significantly toward the top for stability. This was the tallest of the castle's towers, possibly because it covered the approach to the old west gate of the city.

Inside the walls the tower included a crypt chapel, which may be the site of a previous church. The crypt chapel originally had a nave, chancel and an apsidal sanctuary. It is a typical early Norman design with solid pillars and arches. In 1074 D'Oyly and his close friend, Roger d'Ivry endowed a chapel with a college of priests. At an early stage it acquired a dedication to Saint George.

Early in the 13th century the wooden keep on top of the motte was replaced with a ten-sided stone shell keep, 58 feet, closely resembling those of Tonbridge and Arundel Castles. The keep enclosed a number of buildings, leaving an inner courtyard only 22 feet across. Within the keep, stairs led 20 feet down to an underground 12 feet wide stone chamber, with an Early English hexagonal vault and a 54 foot deep well providing water in the event of siege.

http://opendomesday.org/name/446000/robert-doilly/ for list of properties