How does The Polish Rider elucidate its Attribution to Rembrandt?
The first western scholar to discuss the painting was Wilhelm von Bode who in his History of Dutch Painting (1883) stated that it was a Rembrandt dating from his "late" period, that is, 1654. Somewhat later, Abraham Bredius examined the picture quite closely and had no doubts that its author was Rembrandt. At the beginning of the twentieth century, Alfred von Wurzbach suggested that Rembrandt's student Aert de Gelder might have been the author, but his opinion was generally disregarded. Throughout most of the twentieth century, there was general agreement that the painting was indeed by Rembrandt and even Julius S. Held, who at one time questioned its Polish connection, never doubted Rembrandt's authorship. However, in 1984, Josua Bruyn, then a member of the Rembrandt Research Project (RRP) tentatively suggested that certain characteristics of the work of Willem Drost, another student of Rembrandt, could be observed in the painting. Though the mysterious and somewhat solemn expression on the Rider's brilliantly painted face point to Rembrandt, The Polish Rider is unlike Rembrandt's other work in certain other ways. In particular, Rembrandt rarely worked on equestrian paintings, the only other known equestrian portrait in Rembrandt's work being the Portrait of Frederick Rihel, 1663 (National Gallery, London).But Bruyn's remained a minority opinion, the suggestion of Drost's authorship is now generally rejected, and the Frick itself never changed its own attribution, the label still reading "Rembrandt" and not "attributed to" or "school of". More recent opinion has shifted even more decisively in favor of the Frick, with Simon Schama in his 1999 book Rembrandt's Eyes, and scholar Ernst van de Wetering, chair of the Rembrandt Project (Melbourne Symposium, 1997), both arguing for attribution to the master. Those few scholars who still question Rembrandt's authorship feel that the execution is uneven, and favour different attributions for different parts of the work.  A 1998 study published by the RRP concluded that another artist's hand, besides that of Rembrandt, was involved in the work. Rembrandt may have started the painting in the 1650s, but perhaps he left it unfinished and it may have been completed by someone else.
Rembrandt Research Project Aert de Gelder Dutch Rembrandt Willem Drost Abraham Bredius Ernst van de Wetering Simon Schama National Gallery Julius S. Held