The last couple of days at the British Library have mainly been looking at Leibniz’s work as a historian. He was employed by the Duke of Hanover as a librarian, and tasked with writing the family history. He kept going further and further back, eventually deciding to begin with Charlemagne in 768, and planning to go up to 1235, a date he later revised to 1024. When Leibniz died he had reached 1005. The Protogaea was the pre-history to all this; an account of the very soil the family had come from. The family were not impressed by his slow progress, continual distractions, and that he got nowhere close to their own time.
The Annales Imperii Occidentis Brunsvicenses was the eventual publication of Leibniz’s labours as a historian, but it did not appear until over a hundred years after his death, in the first three volumes of the Pertz edition of his Gesammelte Werke. Those three volumes comprise 2,300 pages. In his own lifetime Leibniz published short pieces deriving from this work that can be found scattered in various places. The fifth series of the new Akademie edition of his writings will contain the historical and linguistic works, but so far not a single volume has been published. (I say ‘new’, but this is the edition that has been ongoing since 1923.) The first series has the political and historical correspondence but that’s not complete either, although 23 volumes have been produced and other material is available online. I’ve not even begun to look at that.
Leibniz has been criticised, for example by Lewis Spitz, for not being careful with references and sources as a historian, but while working on the Annales he compiled a huge amount of source material. Much was published in his lifetime, including a collection of legal writings in the Codex juris gentium diplomaticus in 1693, which he then supplemented by a ‘mantissa’ in 1700, itself in two large volumes. His preface to the Codex is an important contribution to his political theory. He compiled medieval imperial chronicles in two volumes of the Accessiones Historicae, and loads of other documents in the three volumes of the Scriptores rerum Brunsvicensium. These include canon law, civil law, papal proclamations, histories, chronicles and so on. From the materials he left behind at his death Georg Eckhardt compiled two enormous volumes (just shy of 4,500 pages in total) of the Corpus historicum Medii Ævi and Christian Ludwig Scheidt and his successor produced five volumes of the Origines Guelficae.
The British Library has all of the above, and so my survey work has been made immeasurably easier by that. That said, it’s not always been easy to locate things in the catalogue or for the librarians to find the right thing on the shelf. I’ve been surveying this material, rather than trying to read it. I’ve been reading Leibniz’s prefaces, some of the shorter pieces, and secondary literature. For my current purposes that is sufficient. But there is almost nothing on Leibniz as a historian in English, and an enormous amount of source material – and this is just what is published; there is almost certainly loads more to be catalogued and examined in the archive. When the ‘great’ philosophers are being examined in ever more recondite ways in order to try to find some tiny aspect that has not yet been done to death, it’s remarkable that such a major concern of such a major figure is so little known. The major study of this work is Louis Davillé’s hundred year old study Leibniz Historien: Essai sur l’activité et la méthode historiques de Leibniz. As far as I know, nothing close has been attempted in any language since. There are a few works in German which are either specialised on a single aspect or briefer surveys, and the Spitz piece mentioned above which is a bit grumpy. There is a major project of historical retrieval here for someone with the skills, time and patience I lack.