Here's an instrument that you might not hear mention of in conversations about the origins of the piano. It's the "dulce melos". According to its description:
"It is essentially a keyed dulcimer whose action is a precursor of certain early pianos. A staple-shaped 'hammer' carries a slip of wood hinged to the key at the back, and when a key is depressed it is thrown up against the strings and returns instantly. There are no dampers, and it is possible, played sensitively, to obtain limited dynamics, which was an advantage over the harpsichord being developed over the same period"
Read more about it here. Who says ya don't learn something new everyday?!