https://daily.jstor.org/why-we-will-never-hear-what-mozart-heard/

"When we play one of Mozart’s or Beethoven’s compositions, or when we hear one, we probably aren’t hearing what they heard or what they thought in their heads as they composed. Their pianos were quite different from the ones we play today. Modern pianos are the product of a 600-year evolution. The instrument has evolved from the mention of Hermann Poll’s clavicembalum in 1397, through various clavichords and harpsichords to the modern grand piano."