This project on the Royal Historical Commission (RHC) of Belgium focuses on its source-publication undertakings and on changing conceptions of which histories were able and allowed to be written with such source-material throughout the Long Nineteenth Century. Founded soon after Belgian independence, the institute's undertakings were inextricably linked to flourishing and contested notions of nationhood. Set up as an extension of this young state and accredited royal status, this institute helped legitimize Belgian statehood but was at the same time in search of its own legitimation. To be able to analyze such legitimization processes, the RHC's philologists and their scholarship are scrutinized in the following way: by going into greater detail about the intentions and decision-processes behind the selection of the RHC's source-publications, the PhD challenges existing literature on this institute's history. Avoiding the pitfalls of relapsing into linear perspectives of the scientification of philological scholarship, the shifts in the RHC's scope are here not dealt with as successive steps in the progressive march of science. Instead, such shifts are addressed from the angle of history of science and the RHC's philology is approached by taking into consideration how the distribution of the supporting 'auxiliary sciences' (e.g. epigraphy, paleography, numismatics, etc.) changed over the various generations of its members. As a result, a more ingrained and substantiated history of the source-conception in the RHC's activity can be offered. In doing so, this projects aims to not only provide an account of the institute's history but to actually historicize the historiography of the RHC.