ABSTRACT
Historians, particularly medieval historians, are vulnerable to the charge that they concentrate their attention upon success - on the successful dynasties, institutions and ideas - and that they thereby misrepresent the past. Thus the political historian sees the ninth century as the crucial period in the evolution of a unitary English kingdom. To comprehend the threat that the Vikings posed, people must first establish, in so far as possible, the size of the armies that terrorized, demoralized and ultimately conquered much of ninth-century England. The accuracy of medieval chroniclers in estimating enemy forces depends upon their access to reliable information and upon their motivation. A single writer may be reliable in some places, wildly inaccurate in others. The Chronicle does occasionally indicate the numbers of Vikings killed in battle. Enemy casualty figures are notoriously the most unreliable of war-time statistics, but again the Chronicle is reticent.
