Although inconsistencies in Schindler's account of Beethoven's life had been called in to question as early as the 1850s and had motivated
Alexander Wheelock Thayer to commence research for his own pioneering Beethoven biography, it was a series of
musicological articles published beginning in the 1970s that essentially destroyed Schindler's credibility. It was demonstrated that Schindler had falsified entries in Beethoven's conversation books, adding many spurious entries after the composer's death in 1827 and that he had exaggerated his period of close association with Beethoven (his claimed eleven or twelve years was likely no more than five or six). It is also believed that Schindler burned more than half of Beethoven's conversation books and removed countless pages from those that survived.
The Beethoven Compendium (Cooper 1991, p. 52) goes so far as to say that Schindler's propensity for fabrication and inaccuracy was so great, virtually nothing he has written about Beethoven can be accepted as fact unless it is supported by other evidence. More recently, Theodore Albrecht has re-examined the question of Schindler's reliability, and as to his presumed destruction of a large number of conversation books, concludes that this widespread belief could possibly have been exaggerated. Although Schindler forged documents and otherwise became notorious as an unreliable biographer and
music historian, his accounts on Beethoven's style of performing his own piano works remain important sources. Dr. George Barth, in his book
The Pianist as Orator (Ithaca, NY:
Cornell University Press, 1992) brings to light an approach to bringing the Beethoven keyboard literature to life, based on Schindler and his testimonies, quite different from the
Carl Czerny accounts on Beethoven the world has accepted since Schindler's forgeries compromised the latter's credibility. Discrepancies in metronome markings by Czerny as well as accounts of Beethoven's own rhythm and tempo choices create a worthier image of Schindler's credibility in that regard, and his valuable perspective on interpretation of Beethoven's piano music. Nevertheless, most scholars and music historians dedicated to historical performances continue to discredit Schindler, especially in his appraisal of Beethoven's alleged flexibility in tempo when performing his own music, and instead continue to rely more on Czerny and Ferdinand Ries, both of whom were more accomplished musicians and knew Beethoven far longer than Schindler. This is summarized by Sandra Rosenblum in her
Performance Practices in Classic Piano Music: Their Principles and Applications (Indiana University Press). ==In film==