XEE4148122 Frederick William IV (1795-1861), King of Prussia, swearing oath on the constitution, 6 February 1850, wood engraving after Paul Buerde, 19th century - Frederic-Guillaume IV (Frederic William IV) of Prussia took oath on the Constitution February 6, 1850 by Unknown Artist, (19th century); Private Collection; (add.info.: Frederick William IV (1795-1861), King of Prussia, swearing oath on the constitution, 6 February 1850, wood engraving after Paul Buerde, 19th century - Frederic-Guillaume IV (Frederic William IV) of Prussia took oath on the Constitution February 6, 1850); Stefano Bianchetti; out of copyright.