Short answers, pulled from the story.
The land now known as Chartwell first appeared in written records on the 2nd of May 1362, when a man named William At-Well sold it. The name itself derives from an Old English phrase meaning rough ground near a spring called Chart Well.
Winston Churchill bought Chartwell from Captain Archibald John Campbell Colquhoun after negotiating the price down to £5,000 in September 1922. The sale concluded officially on the 11th of November 1922 following an auction that had failed to sell the property earlier that year.
During the 1930s when Churchill held no political office, Chartwell became the center of his world where he gathered individuals to assist his campaign against German rearmament. Robin Fedden later described the house as the most important country house in Europe and called it a little Foreign Office serving as the hub of resistance.
Chartwell remained mostly unused during the Second World War due to its exposed position near German-occupied France making it vulnerable to airstrike or commando raid. Lakes were covered with brushwood to make the house less identifiable from the air while security improvements were completed at Chequers.
Winston Churchill suffered a debilitating stroke on the 23rd of June 1953 after collapsing at dinner on 10 Downing Street and was driven immediately to Chartwell. He made a remarkable recovery there before chairing his last cabinet on the 5th of April 1955.
The gardens surrounding Chartwell are predominantly the creation of the Churchills themselves with later input from Lanning Roper who served as Gardens Adviser to the National Trust. Features include the rose garden laid out by Lady Churchill, the water garden with the golden orfe pond, and upper and lower lakes created through ambitious landscaping schemes starting in 1935.