Question: Which major conflict did the author of The Long Week-End participate in?

full_context: Document 1: Jethro Sumner: Sumner was named the commanding officer of the 3rd North Carolina Regiment of the North Carolina Line, a formation of the Continental Army, in 1776, and served in both the Southern theater and Philadelphia campaign. He was one of five brigadier generals from North Carolina in the Continental Army, in which capacity he served between 1779 and 1783. He served with distinction in the battles of Stono Ferry and Eutaw Springs, but recurring bouts of poor health often forced him to play an administrative role, or to convalesce in North Carolina. Following a drastic reduction in the number of North Carolinians serving with the Continental Army, Sumner became a general in the state's militia but resigned in protest after the North Carolina Board of War awarded overall command of the militia to William Smallwood, a Continental Army general from Maryland. After the end of the war in 1783, Sumner helped to establish the North Carolina Chapter of the Society of the Cincinnati, and became its first president. He died in 1785 with extensive landholdings and 35 slaves.
Document 2: James Youll Turnbull: He was a sergeant in the 17th Battalion (Glasgow Commercials), The Highland Light Infantry, British Army during the Battle of the Somme in First World War. On 1 July 1916, Turnbull was awarded the VC for his actions at Leipzig Salient, Authuille, France, where Turnbull's party captured a post of apparent importance, and defended it "almost single-handed[ly]". Later in the day he was killed while engaged in a bombing counter-attack. He was 32 years old.
Document 3: Somerset: Many Somerset soldiers died during the First World War, with the Somerset Light Infantry suffering nearly 5,000 casualties. War memorials were put up in most of the county's towns and villages; only nine, described as the Thankful Villages, had none of their residents killed. During the Second World War the county was a base for troops preparing for the D-Day landings. Some of the hospitals which were built for the casualties of the war remain in use. The Taunton Stop Line was set up to repel a potential German invasion. The remains of its pill boxes can still be seen along the coast, and south through Ilminster and Chard.
Document 4: Oskar Maria Graf: On 1 December 1914, he was drafted for military service. A year later, in 1915, he published his first story, in the magazine Die Freie Straße ["Free street"]. In 1916, Graf was nearly court-martialed for refusing a command. However, after a ten-day hunger strike, he was sent instead to a psychiatric hospital and later discharged from the military.
Document 5: J. C. Dunn: Dunn, who had previously served in South Africa, was Regimental Medical Officer for the Royal Welch Fusiliers during World War I, and is mentioned in the memoirs of both Robert Graves and Siegfried Sassoon. Dunn wrote of his official role that: "The first duty of a battalion medical officer in War is to discourage the evasion of duty ... not seldom against one's better feelings, sometimes to the temporary hurt of the individual, but justice to all other men as well as discipline demands it."
Document 6: The Times: Between 1941 and 1946, the left-wing British historian E.H. Carr was Assistant Editor. Carr was well known for the strongly pro-Soviet tone of his editorials. In December 1944, when fighting broke out in Athens between the Greek Communist ELAS and the British Army, Carr in a Times editorial sided with the Communists, leading Winston Churchill to condemn him and that leader in a speech to the House of Commons. As a result of Carr's editorial, The Times became popularly known during that stage of World War II as the threepenny Daily Worker (the price of the Daily Worker being one penny).
Document 7: The war to end war: During August 1914, immediately after the outbreak of the war, British author and social commentator H.G. Wells published a number of articles in London newspapers that subsequently appeared as a book entitled The War That Will End War. Wells blamed the Central Powers for the coming of the war and argued that only the defeat of German militarism could bring about an end to war. Wells used the shorter form of the phrase, ``the war to end war '', in In the Fourth Year (1918), in which he noted that the phrase had`` got into circulation'' in the second half of 1914. In fact, it had become one of the most common catchphrases of the First World War.
Document 8: John Neville Manners: John Neville Manners (6 January 1892 – 1 September 1914) played cricket for Eton College in Fowler's match in 1910, and died in the early weeks of the First World War on the retreat from Mons. He was immortalised in poem LIV of "The Muse in Arms" by William Grenfell (brother of Julian Grenfell) entitled "To John".
Document 9: Fall of Giants: Fall of Giants is a historical novel published in 2010 by Welsh-born author Ken Follett. It is the first part of the Century Trilogy which follows five interrelated families throughout the course of the 20th century. The first book covers notable events such as World War I, the Russian Revolution, and the struggle for women's suffrage. The sequel "Winter of the World" covers World War II and was published on September 18, 2012. The third book, "Edge of Eternity", covers the Cold War and was published in 2014.
Document 10: The Long Week-End: The Long Week-End is a social history of interwar Britain, written by Robert Graves and Alan Hodge. It was first published in 1940, just after the end of the period it treats.
Document 11: Winston Churchill as historian: The British statesman Winston Churchill was a prolific writer throughout his life, and many of his works were historical. His better-known historical works include: "", "The World Crisis" (a history of World War I), "The Second World War", and "A History of the English-Speaking Peoples". Churchill was awarded the Nobel Prize in Literature in 1953 for "his mastery of historical and biographical description".
Document 12: The Penguin History of the United States of America: The Penguin History of the United States of America is a non-fiction book about the history of the United States written by Hugh Brogan and published by Penguin Books. It was originally titled "The Longman History of the United States of America", published by the Longman company from 1985 through 1999. Longman and Penguin are both part of Pearson PLC. The book starts in the pre-Columbian era and, in the first edition, ends in the mid 1970s. The second edition, or "new edition", added a chapter covering through to the end of the 1980s.
Document 13: Long service leave: Long service leave was introduced in Australia in the 1860s. The idea was to allow civil servants the opportunity to sail home to England after 10 years' service in 'the colonies'. It was 13 weeks for every ten years of service, composed of five weeks to sail back to England, three weeks of leave and five weeks to sail back.
Document 14: United Kingdom–United States relations: Through times of war and rebellion, peace and estrangement, as well as becoming friends and allies, Britain and the US cemented these deeply rooted links during World War II into what is known as the ``Special Relationship. ''In long - term perspective, the historian Paul Johnson has called it the`` cornerstone of the modern, democratic world order''.
Document 15: In Flanders Fields: ``In Flanders Fields ''is a war poem in the form of a rondeau, written during the First World War by Canadian physician Lieutenant - Colonel John McCrae. He was inspired to write it on May 3, 1915, after presiding over the funeral of friend and fellow soldier Lieutenant Alexis Helmer, who died in the Second Battle of Ypres. According to legend, fellow soldiers retrieved the poem after McCrae, initially dissatisfied with his work, discarded it.`` In Flanders Fields'' was first published on December 8 of that year in the London magazine Punch.
ground_truth: World War I
sub_queries: The Long Week-End >> author Answer: Robert Graves
Robert Graves >> conflict Answer: World War I