new bedrooms. However, sensitive to his family heritage, he left the rooms largely untouched, making additions rather than changing the existing spaces of the house. Changes to the main baroque interiors were restricted to details such as stamped leather hangings on the walls of the State Music Room and State Bedroom, and a wider, shallower, but less elegant staircase in the Painted Hall, which was itself later replaced. The contents of the State Apartments were rearranged in 2010 to reflect the way they had looked in the 17th and 18th centuries. 18th-century alterations In the 1760s, William Cavendish, 4th Duke of Devonshire, redirected the approach to Chatsworth. He converted the kitchen in the centre of the north front into an entrance hall, from which guests walked through an open colonnade in the courtyard, through a passage past the cook's bedroom and the back stairs, and into the Painted Hall. He then built a neoclassical service wing for his kitchens that was a forerunner of the 6th Duke's north wing. William Cavendish, 5th Duke of Devonshire, had some of the family's private rooms redecorated and some partition walls moved, but there are few traces of the mid and late 18th century in the public rooms. 19th-century alterations The 6th Duke modified much of Chatsworth to meet 19th-century standards of comfort, suiting a less formal lifestyle than that of the 1st Duke's time. The corridors round the courtyard were enclosed and given a multicoloured marble floor, so that rooms could be easily reached from indoors, and there were more shared living rooms to replace individual guest apartments. The cook's bedroom and the back stairs made way for the Oak Stairs, topped by a glass dome and built at the north end of the Painted Hall to improve internal communications. Along the staircase hang portraits of the first 11 Dukes and some of their family members. The Duke made a library of the long gallery, originally created by the 1st Duke. He was a great lover of books and purchased entire libraries. The Ante-Library in the adjoining room was originally used by the 1st Duke as a dining room and then a billiard room, before the 6th Duke used it for his growing collection of books. This was just one of the rooms where the Duke installed a single-pane window, which he saw as the "greatest ornament of modern decoration". The window in