Wilhelm; Prince of Prussia; eldest son of Wilhelm; Crown Prince of the German Reich; and Cecilie of Mecklenburg-Schwerin; Potsdam 4. 7. 1906 - Nivelles 26. 5. 1940.- "Sibling love; Prince Wilhelm and Prince Louis Ferdinand of Prussia". -(Prince Wilhelm; left; with his brother Louis Ferdinand; 1907-1994; in front of the Marble Palace in Potsdam).Photomontage (Neue Photographische Gesellschaft; Berlin-Steglitz); edited as a postcard Berlin (published by Gustav Liersch & Co.) 1908.Private collection.