The image of ‘writing from the heart’ – the subject of this chapter – is central to the texts produced by the Helfta nuns, and is prominent in both Mechthild of Hackeborn’s Liber specialis gratiae and Gertrude of Helfta’s Legatus divinae pietatis. Instances of the Sacred Heart need to be seen in a wider context, including scholastic texts as well as mystical traditions, which consider processes of wounding and their affinity with writing. In this sense, it is important to look at where the Legatus may have found inspiration for the motif of the heart, exploring resemblances to Victorine ideas, and texts by writers such as Bernard of Clairvaux, Alan of Lille, and Mechthild of Magdeburg. The influence of Mechthild of Magdeburg’s Flowing Light of the Godhead, which was composed before the Liber and the Legatus, has gone largely unnoticed. The following investigation addresses this issue and shows that ideas central to ‘the scriptorial heart’ – in Helfta, related to Christ’s Passion – are to be found in Mechthild’s Flowing Light. Indeed, ‘writing from the heart’ is more of a compositional principle for the Helfta nuns than a mere literary trope, as I show in this chapter.1 Imaginary texts in visions are intertwined with imagery of writing connected to the heart; in this way, repeated references to the productive heart, on the basis of the medieval understanding of the heart as seat of the soul, illustrate how the mystical union is communicated in bodily terms.