Friedrich von Keller ( 1840 - 1914 ) was a painter. Friedrich von Keller s works have been put up for auction numerous times, with realized prices surpassing estimated prices, varying from 213.9 USD for Portrait eines bärtigen Mannes in 2009 to 3300 USD for (A Pair) A Musical Interlude and In the Tavern in 2010 , based on the size and medium of the artwork.