The earliest record of Burderop dates from 1219 when it existed as Burithorp in the west of the parish of Chiseldon. Between 1305 and 1355 land belonging to the Cardeville family including the land that is now Burderop was given to Hyde Abbey and became known as Burderop manor.
The Abbot dissolved his estates to the King in 1538 and in 1540 Burderop manor and Monkebaron grange were granted with Chiseldon to Sir John Bridges, which on his death passed to Sir Edmund Bridges. Thomas (II) Stephens of Burderop purchased Burderop in 1561. The main farmhouse became a manor house soon after this transfer, with the grange remaining as a farmhouse. Between 1596 and 1611 the estate was inherited through the Stephens family. Queen Elizabeth I stayed at Burderop in 1592 on the way from Ramsbury to Down Ampney. The bed she is meant to have slept on, of carved and painted oak, is preserved in America. The manor house was aggrandised prior to the Queen’s visit.
A 1619 lease refers to Monkebaron grange as ‘the old farmhouse’, with the main farmhouse known as the ‘manor house’. It mentions a new stable block belonging to the old farmhouse. This stable still exists, to the east side of the manor house forecourt. That same year Sir William Calley purchased Chiseldon and Burderop manors, unified as Burderop Estate, totalling 1,2 acres, with the accompanying purchase documents referring to a new manor house. William (I) Calley, made his fortune as an importer of silks and other cloths, gold and silver, cochineal and Seville oil. He subsequently obtained the contract to clothe the Spanish army in the Netherlands c.1607, and it is with the proceeds of this that the Estate was acquired.
On his death the Estate was inherited through the male line of the Calley family. As tradition, at times of marriage or inheritance, changes were made to property. At least three were recorded at Burderop, including by William (II) in 1660-1664, with the ‘Tudor’ wing built as a service range and demolition of a gallery running across the top of the main stair. From 1664 there is no further mention of Monkebaron, the old farmhouse, so it is assumed to have been demolished. A new farmhouse (now referred as the Cottage) was constructed, which remains to the west of the manor house forecourt.
A major re-building of the manor house started in 1731 for William (IV). The manor house was made into a Palladian building, by regularising the elevations, raising the building by a whole storey and the addition of the two-storey porch to the west. The Granary, Walled Garden and North Wing were also constructed and a brew-house was built on the site of Monkebaron grange. The work was led by Architect Francis Smith of Warwick. The oldest surviving plan of 1773, shows the landscape gardens and lawn to the east of the House and the principal access route running south, with a second drive to the farm.
Between 1811-1831 race meetings were held at Burderop Down by Thomas Calley, who was then High Sheriff of Wiltshire. In 1821 Thomas Calley was brought to trial for debt, resulting in bankruptcy in 1823. The Burderop Estate was let to obtain funds and in 1845 parts of the Estate had been sold off. Burderop farm remained, listed as totalling 984 acres.
During the C19 the Calley’s continued to host the landed gentry and their great friend King Edward VII, who visited on several occasions with his friends. The last male direct line of the Calley family, Thomas Charles Pleydell died in 1932. His wife died in 1954 and her daughter Joan Marion continued to live in the mansion until her death in 1973. The house was left to Sir Henry Calley, of Overtown Manor, a cousin.
Halcrow, now CH2M Hill, bought the house and 30 acres from Henry Calley in 1977. The Mansion was in need of major renovation, alongside conversion of the existing buildings as offices, and a need for additional office space. Two Pavilions were constructed in 1977 and a third in 1990. The renovation and conversion of the Mansion included rebuilding of the principal staircase, repair of moulded plaster ceilings and oak panelling and rebuilding of the central glass dome. On removal of C18 oak panelling for repair, wall paintings were found in four of the first floor rooms, depicting landscapes with animals, foliage and buildings, divided by trompe l’oeil columns. Integral to two were the coat of arms of William (I) Calley, evidence of their painting between 1619 and 1641. The wall-paintings on plaster were removed for restoration and storage in 1978.