For how many years was George Howard's home in the Howard family?
George Howard, 9th Earl of Carlisle: George James Howard, 9th Earl of Carlisle (12 August 1843 – 16 April 1911), known as George Howard until 1889, was an English aristocrat, peer, politician, and painter. Castle Howard:  It is a private residence, and has been the home of the Carlisle branch of the Howard family for more than 300 years.
300 years