Christie's will offer for sale what the auctioneer called the most important private collection of papers related to British wartime leader Winston Churchill.
The collection was assembled over 30 years by Malcolm S. Forbes Jr., a descendant of the Forbes magazine founder, and will be sold in three parts starting in London on June 2.
The London sale is expected to fetch about £1 million ($1.5 million).
The second auction will take place in New York on Dec. 3 and the third in London in the summer of 2011.
The June 2 sale will feature around 150 lots including letters, books, photographs and a cigar. Individual estimates range from £1,000 to £120,000($182,800).
Among the most important lots is Churchill's engagement diary during World War Two which gives detailed information of his daily activities. It is estimated at £80-120,000 pounds.
The diary, kept by private secretaries, records meetings with U.S. President Franklin Roosevelt, Charles de Gaulle of France and Soviet leader Josef Stalin as well as regular Tuesday meetings with the king which began as an evening appointment and soon become a weekly lunch.
The start of the Battle of Britain in July, 1940 is marked by a cabinet meeting followed by lunch with Sir Alfred and Lady Beit and a brief visit to the south coast of England.
The auction also offers Churchill's account of the Battle of Omdurman, the last ever cavalry charge of the British army in which he took part as a young soldier, Christie' said.
In the letter written on Sept. 16, 1898, he described the battle in detail and stated that at one point, having been faced with an enemy of "at the very least 40,000 men", "it was, I suppose, the most dangerous two minutes I should live to see."
