English military strategy failed against Danish forces.

Evidence

To an undue subservience to the Church the English at this time added military mismanagement. … Now the English were confronted with a different type of enemy. The Danes and Norsemen had not only the advantages of surprise which sea-power so long imparted, but they showed both mobility and skill on land. — Winston Churchill, A History of the English-Speaking…, 173

Categorization

• corroborated: 2 independent passages support this claim — Winston Churchill, A History of the English-Speaking…, 173
• XREF: connects to: The Battle of Stamford Bridge ended Scandinavian threats to English rule. — Winston Churchill, A History of the English-Speaking…, 264