The controversy was over the role of Cavalry in future war. The generally held view is that the arme blanche charge was obviously obsolete, and that Cavalrymen clung to it for social and sentimental reasons; British military leaders of the First World War are therefore condemned for their belief in Cavalry. This thesis questions that view. It offers a case-study of the effects of political, economic, strategic and social factors on the debate: the link between operational and social military history; and the use made by the Army itself, of history in forming tactical doctrines. After the major wars from 1861 to 1871 a movement for reform of tactics and training emerged in the Cavalry, questioning the value of the arme blanche. Reformers outside the Cavalry pursued a conflicting policy, based mainly on the belief that the Cavalry could not reform itself, and that an alternative force, the 'Mounted Infantry' should be created. Before the end of the century the internal reformers gained dominance in the Cavalry, but failed to project this to the rest of the Army or the public. Their doctrine combined dismounted action with limited use of the arme blanche, leading to their being classed with the reactionaries by external reformers. The crisis of the controversy came in the Second Boer War (1899-1902) in which the Cavalry's apparent failure resulted from the dogmatic application of the non-Cavalry reformers' theories by the Commander-inChief, Lord Roberts. After the war Cavalry reformers united briefly with the reactionaries to defeat Roberts' version of 'reform i and continued their own progrrurune after his retirement. The First World War showed the correctness of including the arme blanche in their doctrines.