The great difficulty of history, as it must be written in modern times, arises from the multitude and complication of the events which have to be recorded. So intimately connected have the States of Europe been since the rise of modern civilisation, that he who writes the annals of one must write the history of all. The progress, internal and external, of all its powers must be brought forward abreast; and such is their number and importance, that not only is the historian oppressed with the variety and complication of his materials, but he finds it next to impossible to produce interest in the reader amidst such a sea of details; and often fails, from the impossibility of attaining that essential requisite in the rousing of human sympathy--unity of emotion. Add to this the infinity of subjects a historian even of an individual state must now embrace, and which almost overwhelm the exploits of particular men by their multitude and complication. Strategy, statistics, trade, navigation, commerce, agriculture, taxation, finance, currency, paper credit, poor laws, agriculture, socialism, chartism, form a few of the topics, any one of which would require volumes for its elucidation, yet none of which can be omitted without exposing the historian to the imputation, from some one or other, of having overlooked the most important part of his subject. So great is this difficulty, so extensive the embarrassment it produces, that it may safely be pronounced to be insurmountable by any effort, how great soever, unless the endeavours of the historian are aided by unity of interest in the subject, or overpowering greatness of influence in the characters with whom he has to deal. But it is, perhaps, only in the wars of the Crusades, of the Succession in Spain, and of the French Revolution, that such unity of interest is to be looked for, or such surpassing grandeur of character is to be found, from the achievements of a Richard Coeur-de-Lion, a Marlborough, or a Napoleon.