Built in 1138 by Henri de Blois, Bishop of Winchester, grandson of William the Conqueror, the castle was to become the home of the Bishops of Winchester for over 800 years. The original building was demolished by Henry II in 1155 after the Anarchy and then rebuilt in the late 12th and early 13th centuries. In the early 15th century, it was the residence of Cardinal Henry Beaufort who presided at the trial of Joan of Arc in 1431. It is for this reason that St Joan of Arc's Church in Farnham is dedicated to her. The castle was slighted again after the Civil War in 1648. Since then more buildings have been constructed in the castle's grounds, the most impressive being those built by Bishop George Morley in the 17th century.
The architecture reflects changing styles through the ages, making it one of the most important historical buildings in the south of England. It is an impressive stone motte and bailey fortress, which has been in continuous occupation since the 12th century. The large motte was formed around the massive foundations of a Norman tower and then totally enclosed by a shell keep, with buttress turrets and a shallow gatehouse. Attached to the motte is a triangular inner bailey, with a fine range of domestic buildings and a fifteenth-century brick entrance tower. The formidable outer bailey curtain wall has square flanking towers, a 13th-century gatehouse and a large ditch.
The castle is set in five acres (20,000 m2) of gardens overlooking the town of Farnham.
During the Second World War, the castle was the location of the Camouflage Development and Training Centre. Here, artists such as Roland Penrose, Stanley William Hayter, and Julian Trevelyan as well as the magician Jasper Maskelyne were trained in the arts of military camouflage.
For the last fifty plus years the castle has been an intercultural training and conference centre.
With the help of the Heritage Lottery Fund, the keep and Bishop's Palace have undergone a complete renovation, and are now managed by Farnham Castle. The keep re-opened in July 2010 displaying the extended research that has been undertaken into the history surrounding the castle; there is also an exhibition on site open to the public covering the 900 Years of Living History of Farnham Castle
Thabo Mbeki, the second democratic President of South Africa (1999–2008), married his wife there in 1974.
English Heritage has guardianship of the keep but Farnham Castle now manages the visitors to the keep. Entry is free. Local guides provide tours of the Bishop's Palace (certain days only, charge applies).
- British Listed Buildings accessed 3 March 2013
- Roger Cox (10 January 2006). "Surrealist who tried to paint a whole nation green". The Scotsman. Retrieved 17 January 2016.
- The Farnham Castle International Briefing and Conference Centre
- "Archived copy". Archived from the original on 2011-09-27. Retrieved 2011-08-03.
- Three Palaces of the Bishops of Winchester, 2000, English Heritage