 It contains the office of the Presiding Officer, two Deputy Presiding Officers, the Parliament's Chief Executive, and other staff.The mansion house was built in 1681 for Charles Maitland, Lord Hatton and then bought by William Douglas, 1st Duke of Queensberry in 1686.He died in the house in 1695 and it then passed to his son, James Douglas, 2nd Duke of Queensberry, who was one of the Scottish peers signing the Treaty of Union in 1707.