Anton Raphael Mengs ( March 12 , 1728 â `` June 29 , 1779 ) was a German painter . He worked in Rome , Madrid , and Saxony . Anton Raphael Mengs ( March 12 , 1728 -- June 29 , 1779 ) was a German painter , active in Rome , Madrid and Saxony , who became one of the precursors to Neoclassical painting .