Single-sheet charters and coin epigraphy provide valuable evidence for the development of representations of the Old English dental fricative in the seventh and eighth centuries. This evidence indicates differing Kentish and Mercian practices up to the 780s, when scribes in both areas rapidly adopt <ð> to represent this sound. In Kent, occasional experimentation with this character from perhaps as early as the reign of Eadbald (616–40 ad) may suggest a lengthy period of gradual adoption prior to the rapid increase. Mercian practice instead shows an abrupt adoption, which is perhaps the result of reform according to external (perhaps Kentish) models.