ABSTRACT
The historian of nineteenth-century Europe is faced with so vast a quantity of source material, most of it relatively accessible, that he must either restrict his research to a very small field of study, or else be extremely selective, not merely in the sources which he employs, but in those which he consults. Thus the historian studying a mere six months of the foreign policy of one Great Power in the second half of the century would find relevant material in the archives of many countries – material contained in a great many bound volumes, files or boxes of despatches. If he then decided that it was necessary to consider public opinion with regard to his theme, he might feel obliged to consult the European press for the period, and could thus give himself an almost endless task. Historians of earlier centuries may find that their sources are too few: the medievalist, with a limited number of relevant documents, will spend much time and energy in considering the precise validity and significance of each precious piece of evidence. The nineteenth-century historian must, obviously, also be sure of the authenticity and importance of the smallest document, but, because of his nearness in time to his sources, this will usually prove a comparatively easy task. His more difficult task will certainly be that of selection – of deciding which piece of evidence to use, and which to discard, which factors to consider and which to omit.
