Provenance The research is about the painting 'Portrait of William III. of Orange- Nassau' (carried off by the french army Louvre in 1795, Musée des Beaux Arts de Lyon appendant preliminary work portrait painting was a gift (Deal) to William III. of Orange-Nassau, Governor of the Netherlands, King of England, Scotland and Ireland in 1672 (as William II. and "King Billy"). few secured works of Jan Davidsz. De Heem First Coalition between the revolutionary France and Netherlands, abducted in 1795, under Ius belli, the right on war and spoils of war, french army to the Louvre in France remained until 1795 in the dutch royal house (Orange) paintings gallery Wilhelm V. Batavus (1748-1806), in La Haye. few secured most significant artworks concrete historical background of the order placed, a price agreement reached and much more are known. Informations workshop practice passed on numerous drawings of plants to his sons, which were also artists. pool of drawings. Quote translated Gerhard Renken: "A so far barely perceived curiosity in this context is the lack of certified paintings fate of his study sheets can only be speculated." (Weltkunst connection with the discovered museum scientists, art historians and research the opportunity henceforth to identify paintings, single- handedly made by through objectively verifiable findings only "Document documents a study elaboration.