This paper presents the results of a case study of thirteenth-century wax seals from St Ethelred’s Hospital, Hereford. When medieval matrices were impressed into soft wax hand prints were often left on the reverse of the seal. Using modern forensic techniques to capture and compare these prints provides evidence about the process of sealing and its relationship to the individual matrix owner. Seals with the same print on the reverse could be impressed with different matrices, and impressions of the same matrix have different prints on the reverse. The impressing of the matrix was not then, as has been claimed, the responsibility of the matrix owner as the only way to impress their identity into the wax. This evidence allows a reappraisal of administrative developments in sealing, and the separation of the process of sealing from both the performance of livery of seisin and the seal owner.