Complex sentence: The earliest version was known as the Clavier Melodique ("melodious keys "), circa 1831, was made by Pichenot Jeune ("Young Pichenot"), and was probably the first accordion capable of playing a melody.
Split into simpler sentences: The earliest version was known as the "Clavier Melodique" ("melodious keys "), circa 1831. It was made by Pichenot Jeune ("Young Pichenot"), and was probably the first accordion capable of playing a melody.