the _Accessiones historicae_ (1698-1700) and the _Scriptores rerum Brunsvicensium_; the latter of these, containing documents centring round the history of the Welf family, was published in three volumes at Hanover (1707-1711). Leibnitz worked at another collection, the _Origines Guelficae_, which was completed and issued by his pupils (Hanover, 1750-1780), and also at _Annales imperii occidentis Brunsvicenses_, which, although the most valuable collection of the kind yet made, was not published until edited by G. H. Pertz (Hanover, 1843-1846). Other collections followed those of Leibnitz, among which may be mentioned the _Corpus historicum medii aevi_ of J. G. Eccard (Leipzig, 1723) and the _Scriptores rerum Germanicarum_ of J. B. Mencke (Leipzig, 1728). But these collections are merely heaps of historical material, good and bad; the documents therein were not examined and they are now quite superseded. They give, however, evidence of the great industry of their authors, and are the foundations upon which modern German scholarship has built. In the 19th century the scientific spirit received a great impetus from the German system of education, one feature of which was that the universities began to require original work for some of their degrees. In this field of scientific research the Germans were the pioneers, and in it they are still pre-eminent, with Ranke as their most famous name and the _Monumenta Germaniae historica_ as their greatest production. The _Monumenta_ is a critical and ordered collection of documents relating to the history of Germany between 500 and 1500. It owes its origin mainly to the efforts of the statesman Stein, who was responsible for the foundation of the _Gesellschaft für ältere deutsche Geschichtskunde_, under the auspices of which the work was begun. The _Gesellschaft_ was established in 1819, and, the editorial work having been entrusted to G. H. Pertz, the first volume of the _Monumenta_ was published in 1826. The work was divided into five sections: _Scriptores_, _Leges_, _Diplomata_, _Epistolae_ and _Antiquitates_, but it was many years before anything was done with regard to the two last-named sections. In the three remaining ones, however, folio volumes were published regularly, and by 1909 thirty folio volumes of _Scriptores_, five of _Leges_ and one of _Diplomata imperii_ had appeared. But meanwhile a change of organization had taken place. When Pertz resigned his editorial position in 1874 and the _Gesellschaft_ was dissolved, twenty-four folio volumes had been published. The Prussian Academy of Sciences now made itself responsible for the continuance of the work, and a board of direction was appointed, the presidents of which were successively G. Waitz, W. Wattenbach, E. Dümmler and O. Holder-Egger. Soon afterwards as money became more plentiful the scope of work was extended; the production of the folio volumes continued, but the five sections were subdivided and in each of these a series of