sometimes been regarded as a key stage in the transition to a unified England, but this is no longer the general view among historians in the field. In the words of Simon Keynes, "Offa was driven by a lust for power, not a vision of English unity; and what he left was a reputation, not a legacy." It is now believed that Offa thought of himself as "King of the Mercians," and that his military successes were part of the transformation of Mercia from an overlordship of midland peoples into a powerful and aggressive kingdom.Yorke, Kings and Kingdoms, p. 114. Death and succession Offa died on 29 July 796,Brown & Farr, Mercia: An Anglo-Saxon Kingdom In Europe, p. 310 and may be buried in Bedford, though it is not clear that the "Bedeford" named in that charter was actually modern Bedford.Simon Keynes, "Cynethryth", in Lapidge, Encyclopaedia of Anglo-Saxon England, p. 133. He was succeeded by his son, Ecgfrith of Mercia, but according to the Anglo-Saxon Chronicle Ecgfrith died after a reign of only 141 days. A letter written by Alcuin in 797 to a Mercian ealdorman named Osbert makes it apparent that Offa had gone to great lengths to ensure that his son Ecgfrith would succeed him. Alcuin's opinion is that Ecgfrith "has not died for his own sins; but the vengeance for the blood his father shed to secure the kingdom has reached the son. For you know very well how much blood his father shed to secure the kingdom on his son." It is apparent that in addition to Ecgfrith's consecration in 787, Offa had eliminated dynastic rivals. This seems to have backfired, from the dynastic point of view, as no close male relatives of Offa or Ecgfrith are recorded, and Coenwulf, Ecgfrith's successor, was only distantly related to Offa's line. See also Offacolus Vitae duorum OffarumReferences Sources Primary sources Secondary sources Abels, Richard, "Trinoda Necessitas", in Blackburn, Mark & Grierson, Philip, Medieval European Coinage.'' Cambridge: Cambridge University Press, reprinted with corrections 2006. Featherstone, Peter, "The Tribal Hidage and the Ealdormen of Mercia", in Keynes, Simon, "Cynethryth", in idem, "Mercia", in idem, "Offa", in idem, "Mercia and Wessex in the Ninth Century", in Lapidge, Michael, "Alcuin of York", in Nelson, Janet, "Carolingian Contacts", in Stafford, Pauline, "Political Women in Mercia, Eighth to Early Tenth Centuries", in Williams, Gareth, "Mercian Coinage and Authority", in idem, "Military Institutions and Royal