However, in the historical literature of the Renaissance, two novelties claim our attention, in which the mediæval influence is incontrovertibly manifest. On the one hand we see the retention of a form of exposition which was unusual in antiquity, which was created by the Catholic historians of the later ages (Eusebius, Orosius), and which enjoyed great favour in the Middle Ages,--that which, instead of embracing only the history of a single man, family, or people, embraces universal history. On the other hand there was introduced a mechanical artifice of exposition, having its origin in a practice common in the mediæval schools (the gloss), which had far-reaching consequences. The custom arose of adding notes to printed books of history.[217] Notes have made it possible to distinguish between the historical narrative and the documents which support it, to give references to sources, to disencumber and illustrate the text. It was in collections of documents, and in critical dissertations, that the artifice of annotation was first employed; thence it penetrated, slowly, into historical works of other classes. A second period begins in the eighteenth century. The "philosophers" then began to conceive history as the study, not of events for their own sakes, but of the habits of men. They were thus led to take an interest, not only in facts of a political order, but in the evolution of the arts, the sciences, of industry, and in manners. Montesquieu and Voltaire personified these tendencies. The _Essai sur les moeurs_ is the first sketch, and, in some respects, the masterpiece of history thus conceived. The detailed narration of political and military events was still regarded as the main work of history, but to this it now became customary to add, generally by way of supplement or appendix, a sketch of the "progress of the human mind." The expression "history of civilisation" appears before the end of the eighteenth century. At the same time German university professors, especially at Göttingen, were creating, in order to supply educational needs, the new form of the historical "manual," a methodical collection of carefully justified facts, with no literary or other pretensions. Collections of historical facts, made with a view to aid in the interpretation of literary texts, or out of mere curiosity in regard to the things of the past, had existed from ancient times; but the medleys of Athenæus and Aulus Gellius, or the vaster and better arranged compilations of the Middle Ages and the Renaissance, are by no means to be compared with the "scientific manuals" of which the German professors then gave the models. These professors, moreover, contributed towards the clearing up of the vague, general notion which the philosophers had of "civilisation," for they applied themselves to the organisation of the history of languages, of literatures, of the arts, of religions, of law, of economic phenomena, and so on, as so many separate branches of study.