Owen’s poem takes place against the background of World War I. Readers familiar with the history of warfare will immediately identify the time period from the speaker’s reference to “gas-shells” (line 8). Prior to World War I, poison gas had not been used as a weapon of war. Its introduction thus made it necessary to outfit soldiers with gas masks—or, as the speaker calls them, “clumsy helmets” (line 10). The fact that gas plays such a central role in the poem clearly indicates that it takes place in the early twentieth century. That said, the poem doesn’t technically take place on the front lines of battle. Although the first half of the poem recounts the drudgery and danger of trench warfare, it’s important to recognize that this account is retrospective. That is, the speaker is describing a memory. It therefore isn’t entirely clear how far removed the speaker is from the experience he describes. Is he speaking as someone who has just returned from a war that he’s urging others to stop? Or is he recounting a more distant memory to warn against the threat of a new war? The answer remains unclear.