The themes of “Break of Day in the Trenches” emerge from Rosenberg’s inversion of the traditions of the pastoral poem. Generally, pastorals take place in stylized, idyllic rural settings, often early in the morning; their central figures are usually innocent shepherds, whose comments on life are intended also as pointed criticisms of larger social issues. Although the speaker of the poem does not share the rural background of shepherds, he—presumably, like Rosenberg, an urban poet from the East End of London—unselfconsciously emphasizes three main themes: the horrors of war, the artificiality of political barriers, and the necessity of maintaining human values, especially humor, to endure trench warfare.

In “Break of Day in the Trenches,” the speaker clearly thinks of the war as mass slaughter, hardly a situation where one man’s life—or one man’s effort—amounts to much. The inversion of pastoral conventions indicates this. In the second line, daybreak is called the “old druid Time,” a time of human sacrifice—that is, something to be endured, not welcomed. To the soldiers, day is a time to be dreaded; the horrible reality of war is once again visible when darkness starts “crumbling.” This pastoral is not concerned with idyllic moments but with “shrieking iron and flame/ Hurled through still heavens.” Finally, the rat’s closeness to the speaker is another buried hint of the conditions that prevail, implying that the living speaker has been mistaken for a corpse, the animal’s food supply. This would suggest that the central animal of the pastoral—the sheep—has been replaced in this poem by a rat. This setting is stylized but hardly idyllic.

Further, while it is a part of the horrors surrounding the war, the literary rat also marks a second theme: the artificiality of human barriers. The speaker describes the rat as “cosmopolitan,” implying that it is free of the political barriers that, like trench lines, scar the human landscape. While the English and Germans are physically separated as enemies, they are joined by their subjection to the rat and by their victimization in the war.

Finally, Rosenberg explores a third theme in “Break of Day in the Trenches” growing out of his inverted pastoral: the necessity of humor in the midst of horrors. Rosenberg’s contemporary, the English poet Wilfrid Owen, also used pastorals to throw the horrors of war into high relief. Although his poems are compassionate, Owen’s tone is almost uniformly bitter. Rosenberg, for his part, makes use of a lighter tone, although his social criticism is as severe and often as biting. The speaker refers to the grim humor of the trenches several times in the poem: The rat is “sardonic” and “Droll,” and it “inwardly grin[s]” as it crosses no-man’s-land. Juxtaposed against this grim humor, the charnel images have all the more power. For instance, the speaker asks questions of the rat that no one, certainly not the soldier himself, can answer: “What do you see in our eyes/What quaver—what heart aghast?” In the face of these unanswerable questions, it is easy to believe that the soldiers are the butt of some hideous cosmic joke. Only the speaker’s humor and his relief at a temporary moment of safety enable him to pose these questions.