Alexander Guthrie (Alastair) Denniston (1 December 1881–1 January 1961) was a British codebreaker in Room 40 and first head of the Government Code and Cypher School (GC&CS). Dennistion was appointed operational head of GC&CS in 1919 and remained so until February 1942. December 1 is the 335th (in leap years the 336th) day of the year in the Gregorian calendar. ... 1881 was a common year starting on Saturday (see link for calendar). ... January 1 is the first day of the calendar year in both the Julian and Gregorian calendars. ... 1961 was a common year starting on Sunday (link will take you to calendar). ... In the history of cryptography, Room 40 (formally I.D. 25) was the room in the Admiralty which was the first location of the British cryptography effort during World War I. It was formed shortly after the start of the war in October 1914, as a result of codebooks and... The Government Communications Headquarters (GCHQ) (previously named the Government Code and Cipher School (GC&CS)) is the main British intelligence service providing signals intelligence (SIGINT). ... 1919 was a common year starting on Wednesday (see link for calendar). ... This article is about the year. ...

Denniston was born in Greenock, the son of a medical practicioner. He studied at the University of Bonn and the University of Paris. Greenock (Grianaig in Scottish Gaelic) is a town (burgh of barony) in the district of Inverclyde in Western Scotland. ... The main building, viewed from the Hofgarten. ... The Sorbonne, Paris, in a 17th century engraving The historic University of Paris (French: Université de Paris) first appeared in the second half of the 12th century, but was in 1970 reorganized as 13 autonomous universities (University of Paris I–XIII). ...

In 1914 he helped form Room 40 in the Admiralty, an organisation tasked with intercepting and deciphering enemy messages. In 1917 he married a fellow Room 40 worker, Dorothy Mary Gilliat. After World War I, Room 40 was merged with its counterpart in the Army, MI1b, to become the Government Code and Cypher School in 1919. Denniston was chosen to run the new organisation. 1914 is a common year starting on Thursday. ... In the history of cryptography, Room 40 (formally I.D. 25) was the room in the Admiralty which was the first location of the British cryptography effort during World War I. It was formed shortly after the start of the war in October 1914, as a result of codebooks and... 1917 was a common year starting on Monday of the Gregorian calendar (see link for calendar) or a common year starting on Tuesday of the Julian calendar. ... World War I was primarily a European conflict with many facets: immense human sacrifice, stalemate trench warfare, and the use of new, devastating weapons - tanks, aircraft, machineguns, and poison gas. ... 1919 was a common year starting on Wednesday (see link for calendar). ...

With the outbreak of World War II in 1939, GC&CS greatly expanded and relocated to Bletchley Park. In February 1942, GC&CS was reorganised and Denniston was placed in charge of a civil and diplomatic division in London, while Edward Travis succeeded him at Bletchley Park overseeing the work on military codes and ciphers. He retired in 1945, and later taught French and Latin in Leatherhead. World War II was a truly global conflict with many facets: immense human suffering, fierce indoctrinations, and the use of new, extremely devastating weapons like the atom bomb World War II, also known as the Second World War, was a mid-20th-century conflict that engulfed much of the globe... Hey. ... During World War II, British and American cryptographers at Bletchley Park broke a large number of Axis codes and ciphers, including the German Enigma machine. ... This article is about the year. ... Sir Edward Wilfred Harry Travis (24 September 1888–23 April 1956) was a cryptographer, becoming the director of Bletchley Park during World War II. Travis joined the Navy in 1906, and served on the HMS Iron Duke. ... 1945 was a common year starting on Monday (link will take you to calendar). ... Leatherhead is a medium-sized town in Surrey, on the River Mole. ...

Denniston was awarded a CBE in 1933 and a CMG in 1941.. Commanders Badge of the Order of the British Empire The Most Excellent Order of the British Empire is an order of chivalry established on 4 June 1917 by George V. The Order includes five classes in civil and military divisions, in decreasing order of seniority: Knight or Dame Grand... 1933 was a common year starting on Sunday (link will take you to calendar). ... On the Orders insignia, St Michael is often depicted subduing Satan. ... 1941 was a common year starting on Wednesday (link will take you to calendar). ...