Bolsover occupies the hilltop site of a medieval fortress built by the Peverel family. The wealthy Sir Charles Cavendish – who already owned several other great mansions, including one only a few miles away -bought the old fortress in 1612 and began work on his Little Castle project. His son William – playboy, poet, courtier and later Civil War Royalist general and first Duke of Newcastle – inherited the Little Castle in 1617 and set about its completion, assisted by the architect John Smythson. What resulted was a kind of ‘toy keep’, housing tiers of luxurious staterooms. The exquisitely carved fireplaces, and richly-coloured murals and panelling of its miraculously preserved and beautifully restored interiors still take the visitor on an allegorical journey from earthly concerns to heavenly (and erotic) delights.
William also added the vast and stately Terrace Range overlooking the Vale of Scarsdale, now a dramatic roofless shell. To show off his achievement, in 1634 he invited King Charles I and his court to Love’s Welcome to Bolsover, a masque specially written by Ben Jonson for performance in the Fountain Garden. Finally he constructed the cavernous Riding House with its magnificent roof and viewing galleries, among the finest surviving indoor riding schools in the country and a landmark in British equestrianism: here he indulged his passion for training great horses in stately dressage.
(Exert from English Heritage site)