Question: For how many years was George Howard's home in the Howard family?

Context paragraphs:
Charles Howard, 20th Earl of Suffolk: Charles Henry George Howard, 20th Earl of Suffolk, 13th Earl of Berkshire, (2 March 1906 – 12 May 1941) was an English bomb disposal expert who was also an earl in the Peerage of England, belonging to the ancient Howard family.  He was styled Viscount Andover until 1917.  He is most famous for being responsible for rescuing a team of French nuclear scientists and the entire world stockpile of heavy water from France to England in the face of the imminent French defeat in 1940.

Colborne Lodge: Colborne Lodge is a historical museum located in an 1836 home in Toronto's High Park.  John George Howard, an architect, engineer, and prominent Toronto citizen built this house, which became the property of the city following his death in 1890.

Castle Howard: Castle Howard is a stately home in North Yorkshire, England, 15 mi north of York.  It is a private residence, and has been the home of the Carlisle branch of the Howard family for more than 300 years.

George Howard, 13th Earl of Carlisle: George William Beaumont Howard, 13th Earl of Carlisle (born 15 February 1949), styled Viscount Morpeth from 1963 to 1994, is a British nobleman, politician, and hereditary peer.  He inherited the earldom of Carlisle in 1994, upon the death of his father, Charles Howard, 12th Earl of Carlisle.  A member of the Howard family and a kinsman of the Duke of Norfolk, he is also a co-heir to the baronies of Greystock and Clifford.

Rex Salas: Rex Salas (born March 16, 1962) is an American record producer, songwriter, musical director, and music arranger.  Best known in recent years for his work as the musical director for Janet Jackson on several of her tours, Salas has worked with Vanessa Williams, Justin Timberlake, Cher, Boyz II Men, Robert Palmer, Mariah Carey, Stevie Wonder, Lionel Richie, JC Chasez, Earth, Wind and Fire, will.i.am, Robin Thicke, 50 Cent, Jessica Simpson, Nicole Scherzinger, Taylor Dayne, Lindsay Lohan, Adam Levine, Brandy, Maxwell, Leona Lewis, Brian McKnight, Teddy Pendergrass, The Isley Brothers, The Jacksons, UB40, Jeffrey Osborne, All-4-One, Johnny Gill, George Howard, Gladys Knight, The Gap Band, Lalah Hathaway, Jasmine Guy, Tatyana Ali, James Ingram, Corbin Bleu, Patti Austin, Lakeside, The Mac Band, Klymaxx, Chuckii Booker, The Dazz Band, Chanté Moore, Patrice Rushen, Tease, Atlantic Starr, Lenny Williams, Barbara Weathers, Miki Howard, Rebbie Jackson, Aly & AJ, Joyce Kennedy (Mother’s Finest), Paul Jackson, Jr., Brian Simpson, Vesta Williams, Level 42, Sheena Easton and more.

Charles Howard (courtier): Charles Howard was a gentleman at the court of Henry VIII of England.  He was the second son of Lord Edmund Howard and the elder brother of Sir George Howard.  As a scion of the mighty Howard family, his uncle, Thomas Howard, 3rd Duke of Norfolk was able to find him a position at court.  Charles' fortunes improved in 1540, when his sister, Catherine Howard became the King's fifth wife.  Charles went on to create a mesalliance with the King's niece, Margaret Douglas, the daughter of Henry's sister, Margaret Tudor, queen dowager of Scotland.

Howard family: The Howard family is an English aristocratic family founded by John Howard who was created Duke of Norfolk (3rd creation) by King Richard III of England in 1483.  However, John was also the eldest grandson (although maternal) of the 1st Duke of 1st creation.  The Howards have been part of the peerage since the 15th century and remain the Premier Dukes of the Realm in the Peerage of England, acting as Earl Marshal of England.  After the English Reformation many Howards remained steadfast in their Catholic faith as the most high-profile recusant family; two members, Philip Howard, 20th Earl of Arundel, and William Howard, 1st Viscount Stafford, are regarded as martyrs: a saint and a blessed respectively.

Corby Castle: Corby Castle is an ancestral home of the Howard family situated on the southern edge of the village of Great Corby in northern Cumbria, England.

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.  He was the last Earl of Carlisle to own Castle Howard.

James Russell (garden designer): James Russell (1920–1996) was an English garden designer.  He was educated at Eton College and then went to Cambridge University.  His education was interrupted by the Second World War, in which he served for three years.  He was invalided from the army and then managed Sunningdale Nurseries; this had been purchased by his father and a cousin at the outbreak of the war.  He revived the fortunes of the nursery and then started in a career of garden design.  His first commission was for Lord Hastings at Seaton Delaval Hall in Northumberland.  He later worked for the Howard family of Castle Howard in North Yorkshire.  In the 1960s Russell worked with the wives of the 4th and 5th Dukes of Westminster in Eaton Hall, Cheshire, to develop the gardens that had been neglected for many years.  He later worked with the garden designer Graham Stuart Thomas.

Supporting paragraphs: George Howard, 9th Earl of Carlisle Castle Howard
Answer: 300 years