This article contends that the shaping of Mary Slessor into an iconic female missionary exemplifies the ‘deliberate acts of invention’ involved in the creation of imperial heroes and heroines. It contends that there was little that was unique in her practice as a missionary. Rather, the coincidence of her location within an expanding British Empire, the tide of missionary enthusiasm flowing with this expansion, and women's aspirations for autonomous careers, combined in her selection as a symbolic figure for Scottish Presbyterians. In support of this contention, this article sets out the context of missionary practice in the UPC Old Calabar mission, and the context of imperial expansion in southeastern Nigeria in the 1890s and 1900s. It then provides an account of the process of iconisation itself. In doing so, it aims to ‘deconstruct’ the myth of Mary Slessor, indicating the dissonance between myth and historical reality.