Complex sentence: The Piano Sonata No.2, "Concord, Mass., 1840--60" by Charles Ives, commonly known as the "Concord Sonata", is one of the composer's best-known and most highly regarded pieces.
Split into simpler sentences: The Piano Sonata No.2, "Concord, Mass., 1840--60" (commonly known as the "Concord Sonata") is a piano sonata by Charles Ives. It is one of the composer's best-known and most highly regarded pieces.