In the absence of royal collections; it was one of the wealthiest aristocrats of the country who set up the Hungarian National Museum in 1802. Initially a library with a selection of other holdings; the Museum Nationale Hungaricum gradually widened the scope of its collections; and from the 1870s onwards strove for encyclopaedic coverage of human knowledge. Its legal status underwent significant changes; shifting from private to public foundation (1808) and to state museum from 1867. At the same time; its orientation broadened from a national focus towards a regional; and subsequently European; outlook; finally turning to universal collecting when in the last third of the nineteenth century the representation of non-European civilisations came to be included in its programme. Within three-quarters of a century; a small proto-museum; offspring of the Enlightenment and Romantic patriotism; had developed from accumulating national heritage; though still under Habsburg rule; into a full-fledged national museum in the twin capital of the Austro-Hungarian Empire; trying to adopt in the 1870s the model of the British Museum. This stunning expansion soon pushed the institution beyond its capacities and lead instead to the creation of several specialised collections. With this; the museum idea had achieved its triumph in Hungary; and Budapest became a hub with a series of distinctly specialised national museums; while the mission of the National Museum was redefined and re-scaled. Leaving aside its universal and encyclopaedic ambitions; it became dedicated to the mission of caring for the past remnants of the historical territory of the country. This study examines this process (1802-1902); paying particular attention to the changing relationship of imperial and national; ruler and ruled; in the multi-ethnic Carpathian Basin.