[quote name='essexbasscat' post='680183' date='Dec 10 2009, 01:02 PM']good 'un Al Heeley !
the piano was the successor to the harpsichord I think (if that's wrong - please someone say so) around the 1700's or so.
The harpsichord wasn't tuned in 'even' intervals, which made it sound out of tune when played in certain keys ( the same way that if you tune a guitar to sound really nice in one key, it may sound not quite right in others). The answer to this awkwardness with changing keys was to invent an instrument tuned in 'even' intervals - the piano.[/quote]
Not quite, 'well tempered tuning' was used on the harpsichord and clavier before the piano, hence Bach's compostion 'the well tempered clavier' in which the same instrument - his clavier - played pieces that go through all keys.