The article deals with a number of aspects of a Salvator painting rediscovered in 2005 and attributed either in whole or in part to Leonardo da Vinci: the history of the painting’s rediscovery, its copies and variants, the pictorial tradition of Salvator depictions in panel paintings and in book illumination. In this context, the proposal is made to understand the tradition of Salvator depictions in panel paintings against the background of devotional practice of the fourteenth and fifteenth centuries. In particular, the so-called Veronica hymn (Salve sancta Facies) played a major role here. Based on an analysis of the hymn and contemporary prayer practice, the article argues that this practice, with its demand for a ‘face to face’ prayer (facie ad faciem), is also relevant to the pictorial form of Leonardo’s painting. The precise wording of the hymns and prayers, moreover, required a representation ‘as in a dark outline’ (‘seen through a glass darkly’, 1 Cor. 13.12). Leonardo met this requirement of devotional practice with his use of the sfumato.