The perception of the experience of soldiers serving during the First World War has been dominated by youth. Often omitted from the narrative yet present nonetheless was the married soldier: a man whose enlistment brought a clashing of loyalties as they sought to negotiate the perils of military service and balance these with their affections and responsibilities within the home. This dissertation examines the experience of married soldiers from the ‘British World’ – Britain, Australia, and Canada – to deepen the historical understanding of the First World War. To do so, it will examine the epistolary evidence created by the men themselves and sent to their wives to understand how married men, engaged in the job of soldiering in Europe and the Middle East, articulated their new identities as soldiers while simultaneously negotiating the continued affections and responsibilities of husband and father. Several key themes that are understood as integral to the cultivation and sustainment of the soldierly identity are explored. First, the dissertation examines how married men were initially captivated by the wartime discourses of military service as the ultimate expression of manhood, and the motivations they themselves engaged with to justify their enlistment to themselves and their wives. Once enlisted, men began the process of induction into the military. Their adoption of a newly militarised identity was one which was disrupted by the lingering presence of domestic affections and attachments as these men sought ways to mitigate their complete physical alienation from their pre-war lives. Following training, men were sent to the front where they were confronted with the realities of war. Whilst contemplating their new roles as soldiers, either discussing these enthusiastically or with resignation, men were simultaneously anxious to affect their presence in the home, and letters were a chief means by which this was maintained. The final theme discussed is that of the legacy of the war on men’s marital identities, as the cultivation of wider, public, post-war commemorative practices subsumed and largely erased the personal details of men’s lives as a consequence of the destruction wrought by the war.