The written sources are the ones that play the main role in the research on previous art collections. They are extremely important when the works of art themselves were dispersed. It is the case of the set of King Stanislaus Augustus Poniatowski's miniatures. Six inventories of the collection, written between 1783 and 1819, have been saved in PoIish archives. They allow to discuss the set which at the end of Stanislaus Augustus' rule consisted of approximately 300 miniatures. A systematic analysis and confrontation of the inventory descriptions of particular items leeds to the reconstrution of an 'ideal' catalogue, allows to characterize this set deeper, to show its structure and function as well as the value and provenance of the works of art. It also helps us to find out information on the authors of the miniatures and on the iconographic sources. It is obvious that Stanislaus Augustus had a high opinion on his collection of miniatures as he was going to take the whole of it away to the emigration. However, his intention was not realized. The set, which was sold in 1821, has been dispersed. Although some of the miniatures, which might be considered to have their origin from the King Stanislaus Augustus' collection, have been found in Polish and foreign collections, the greatest amount of them are still not being recognized. They are still worth further searching. 14 Illustrations.