A long Eighteenth Century, in continuity with the erudite tradition and the editorial method of Muratori, and a very brief Nineteenth Century, between the first decade after Italian Unification and the eve of the Great War, when a new and (at last) professional generation of scholars (Bonelli, Vittani, Torelli, Manaresi) brought a sweeping change in the field of palaeographic and diplomatic researches and of publications of medieval legal documents: these two are the coordinates (conceptual earlier than chronological) of the present monography, that for the first time deals in a historiographical perspective with a crucial season of Medieval studies in Lombardy, concentrating upon careers, projects and works of its protagonists. The focus is on the editors and editions of charters, but around them we find many other individuals and institutions of the regional and national cultural scene. The Leitmotiv is the delineation of a modern philogical method in the editions of Lombard sources, but the wider context is represented by more general (and stronger, and ideologically characterised) themes of Medieval Studies before and after the national Unification of Italy: the problems of Lombard legacy, the myth of communal age in the Risorgimento culture, the Visconti-Sforza state identity. Finally, this study about editors and editions of medieval charters in Lombardy allows to shed light on the organization of regional historical research, within an intense (and not always simple) dialogue between the hegemonic Milanese capital and the proud local traditions of the other towns and provinces.