Query: What year did the Queen and Albert purchase Balmoral Castle?
Context: Victoria's self-imposed isolation from the public diminished the popularity of the monarchy, and encouraged the growth of the republican movement. She did undertake her official government duties, yet chose to remain secluded in her royal residences—Windsor Castle, Osborne House, and the private estate in Scotland that she and Albert had acquired in 1847, Balmoral Castle. In March 1864, a protester stuck a notice on the railings of Buckingham Palace that announced "these commanding premises to be let or sold in consequence of the late occupant's declining business".