Question: "Dulce et Decorum est", was written in which year, and published posthumously in 1920, a poem written by Wilfred Owen during World War I?

Context articles: Wilfred Owen
Dulce et Decorum est
Futility (poem)
1920 in poetry
Dulce et decorum est pro patria mori
Wilfred Owen: A Remembrance Tale
Jessie Pope
Dominic Hibberd
Insensibility
The Soldier (poem)

Wilfred Edward Salter Owen, MC (18 March 1893 – 4 November 1918) was an English poet and soldier, one of the leading poets of the First World War.
 His war poetry on the horrors of trenches and gas warfare was heavily influenced by his mentor Siegfried Sassoon, and stood in stark contrast both to the public perception of war at the time and to the confidently patriotic verse written by earlier war poets such as Rupert Brooke.
 Among his best-known works – most of which were published posthumously – are "Dulce et Decorum est", "Insensibility", "Anthem for Doomed Youth", "Futility", "Exposure" and "Strange Meeting".
"Dulce et Decorum est" (read , on WikiSource) is a poem written by Wilfred Owen during World War I, and published posthumously in 1920.
 The Latin title is taken from the Roman poet Horace and means "it is sweet and honorable...", followed by "pro patria mori", which means "to die for one's country".
 One of Owen's most renowned works, the poem is known for its horrific imagery and condemnation of war.
 It was drafted at Craiglockhart in the first half of October 1917 and later revised, probably at Scarborough but possibly Ripon, between January and March 1918.
 The earliest surviving manuscript is dated 8 October 1917 and addressed to his mother, Susan Owen, with the message "Here is a gas poem done yesterday (which is not private, but not final)."
"Futility" is a poem written by Wilfred Owen, one of the most renowned poets of World War I.
 The poem was written in May 1918 and published as no. 153 in "The Complete Poems and Fragments".
 The poem is well known for its departure from Owen's famous style of including disturbing and graphic images in his work; the poem instead having a more soothing, somewhat light-hearted feel to it in comparison.
 A previous secretary of the Wilfred Owen Association argues that the bitterness in Owen's other poems "gives place to the pity that characterises his finest work".
 Futility details an event where a group of soldiers attempt to revive an unconscious soldier by moving him into the warm sunlight on a snowy meadow.
 However, the "kind old sun" cannot help the soldier - he has died.
— Wilfred Owen, concluding lines of "Dulce et Decorum est", written 1917, published posthumously this year
Dulce et decorum est pro patria mori is a line from the Roman lyrical poet Horace's "Odes" (III.2.13).
 The line can be translated as: "It is sweet and proper to die for the fatherland."
Wilfred Owen: A Remembrance Tale was a 1-hour 2007 BBC documentary on the life of the First World War poet Wilfred Owen.
 It was presented by Jeremy Paxman and starred Samuel Barnett as Owen and Deborah Findlay as his mother Susan.
 It premiered on BBC One on Remembrance Sunday 2007.
Jessie Pope (18 March 1868 – 14 December 1941) was an English poet, writer and journalist, who remains best known for her patriotic motivational poems published during World War I.
 Wilfred Owen dedicated his 1917 poem "Dulce et Decorum Est" to Pope, whose literary reputation has faded into relative obscurity as those of war poets such as Owen and Siegfried Sassoon have grown.
John William Dominic Hibberd FRSL (3 November 1941 – 12 August 2012) was an English freelance author, academic and broadcaster, best known for his biographies of the poets Wilfred Owen and Harold Monro and his collections (edited with John Onions) of First World War poetry.
 He was an Honorary Vice-President of the Wilfred Owen Association and an Honorary Fellow of the War Poets Association.
"Insensibility" is a poem written by Wilfred Owen during the First World War which explores the effect of warfare on soldiers, and the long- and short-term psychological effects that it has on them.
 The poem's title refers to the fact that the soldiers have lost the ability to feel due to the horrors which they faced on the Western Front during the First World War.
It is often contrasted with Wilfred Owen's 1917 antiwar poem "Dulce Et Decorum Est".
 The manuscript is located at King's College, Cambridge.