Anton Schindler
Ertmann gave a number of public concerts and was most noted for her performance of Beethoven's compositions: Alexander Thayer said that "all contemporary authorities agree, [she was] if not the greatest player of these works at least the greatest of her sex". Anton Schindler suggested that "she grasped intuitively even the most hidden subtleties of Beethoven's works with as much certainty as if they had been written out before her eyes". He also said that "without Frau von Ertmann, Beethoven's music would have disappeared even sooner from the repertory" because she created a musical salon dedicated to preserving his style against the rise of newer, more "fashionable" composers.