Abstract This article identifies one of the great but unstudied paradoxes in the history of early modern global Christianity: that the stronger the desire for a uniform Christian way of life burned, the deeper the fractures between different Christian denominations began to grow. It explores this issue by examining the learned exchanges between the infamous Greek Orthodox Patriarch Cyril Lucaris (1572–1638) and members of the Dutch Reformed Church. These efforts have often been seen as an expression of Christian ecumenism or as evidence that the early modern Middle East had become yet another arena for Catholic–Protestant rivalry. But once motivations on both sides are placed in the distinctly local religious climate that fostered them neither of these explanatory paradigms suffices. On the contrary: a decentred approach to this material reveals how Protestant and Eastern Christian understandings of what reform meant and how it could be attained were completely distinct and irreconcilable. It is thus imperative to resist any simple application to Middle Eastern Christianity of categories rooted in European Christian traditions and, instead, to tease out how different Christian denominations defined reform differently. Only then can we make good on our commitment to approach early modern global Christianity as a pluriform and multi-centred phenomenon.