Friderich Von Keller ( 1840 - 1914 ) was a German painter. Friderich Von Keller s works have been put up for auction numerous times, with realized prices surpassing estimated prices, varying from 3709.2 USD for A worker in the quarry in 2004 to 3869.97 USD for Der fahrende Sdnger in 2005 , based on the size and medium of the artwork.