Several country houses built in Transdanubia (western Hungary) in the early modern age, in the 16-17th centuries are still extant, though most are massively rebuilt. The original state of a mansion can be learnt from archeological investigations, old depictions as well as written sources, particularly inventories. Many of these from the leading aristocratic family archives have been studied by researchers, but the majority are still unpublished. They do not suffice for the perfect reconstruction of the original state of the layout (topography) of the buildings, but their high number allow for statistical inferences to be made about certain general characteristics of usage, furnishing, interrelation of building sections. Constant items in the inventories are: the gate, gatehouse, courtyard, “palace”, the latter including the audience chamber, rooms, staircase, etc. Only the inventories provide a glimpse of the one-time furnishing: lots of tapestries, pictures, carpets, pieces of furniture made these mansions liveable. The sources touch on the gardens in quite some detail, too. This comprehensive paper is closely tied to the author’s earlier published volumes inventorying the country houses (with source publications), and summarizes several decades of research, practical experience and archival investigations within the scope of monument protection.