The standard Anglo-Saxon and Frisian sceatta coin series was gradually abandoned during the 8th century as new forms evolved. Sceatta production became confined to the northern margins of the Anglo-Saxon world - to Northumbria and the See of York, where the archbishop issued his own series. Silver coins were replaced by copies in copper (copper-alloy) known by the generic term styca, an Old English word for 'piece, part'. Styca production was maintained for about a century through successive reigns: Kings Eadberht (A.D. 737-756); Alchred (A.D. 765-774); Aethelred I (First reign A.D. 774-778); Aelfwald (A.D. 778-788); Aethelred I (Second reign A.D. 789-794); Eanred (A.D. 810-840); Aethelred II (First reign A.D. 840-844); Redwulf (A.D. 844); Aethelred II (Second reign A.D. 844-848); Osberht (A.D. 848-867); and several Archbishops of York: Ecgberht (A.D. 732-766); Eanbald II (A.D. 796-830); Wigmund (A.D. 837-854). Wulfhere (A.D. 854-900)], issued silver and copper stycas only.