The British colonial government frustrated European missionaries’ desire to convert Northern Nigeria by curtailing Christian proselytization. This chapter situates missionaries’ tumultuous relationship with the state in the emergence of secularism as an imperial technique of managing religions and religious difference. That technique involved the government’s insistence on its separation from Christian missions, and its indirect rule of the territory through Muslim chiefs. Colonial administrators resolved that paradox–of the state’s rhetoric of separation from Christian missions even while the state remained intimate with Muslim elites–in one of two ways. Some administrators emphasized the superiority of the religious liberty of Muslims over the missionary desire to proselytize; others stressed the imperative for the state to be separate from what remained of the precolonial Sokoto caliphate. As administrators latched on to either argument, so did colonial subjects also deploy either notion to further their agenda. What emerges is a story of a struggle between imperial bureaucrats, Christian missionaries, and Muslim chiefs over the governance of religious difference.