to the Continent at the same time (both events recorded in the Anglo-Saxon Chronicle), can be seen as a tactical response to the effectiveness of the strategic offensive posed by the construction of the Burghal system. The ratification of a mutually agreed boundary to the east of London, in Alfred and Guthrum's Treaty, between Guthrum's new Viking kingdom of East Anglia and Alfred's newly won territory, can best be ascribed to this time. These developments gave Alfred control of London and its surrounding territory, which included a good length of the strategically important Watling Street as it approached London. This interpretation is supported by the issue at this time of the special celebratory London Monogram coinage from the London mint, now under the control of Alfred, and by the issue at the same time of coins from Oxford and Gloucester in southern Mercia. The fact that the Burghal Hidage does not include London, only taken in late 879; that many of the burhs recorded in the document were of a temporary nature and were only replaced by more permanent fortified sites later on; and that its organisation reflects a strategic offensive against the Viking presence in Mercia and London, are factors which argue strongly that the Burghal Hidage is a prescriptive list describing a system which was in process of being planned and implemented before late 879. It is therefore likely to have originated in a context in which the logistics of the system and the means for its implementation and support were being worked out in practice on the ground. The fact that the construction of a burh at Buckingham by Alfred can be logically placed within this strategic scheme at this period (878-9), removes the necessity of having to place the creation of the original version of the Burghal Hidage after the first documentary mention of Buckingham in 914. Its composition can therefore be most appropriately placed in a West Saxon context, rather than one which relates to the formation of burhs and shires in Mercia in the early 10th century – to which situation it has no relevance. In Wessex a number of the burhs which were part of the system recorded in the Burghal Hidage, and which were merely fortresses rather than fortified towns, were in many cases replaced at a later date by larger fortresses which were fortified towns. The received view of the date