Tchaikovsky never composed a cello concerto, but he did write this work, which is a tune with a set of variations. It is called "Rococo" because the music is based on the style that was popular in the late 18th century, the period during the Classical period known as Rococo, the time of composers such as Mozart. The main theme is an original theme by Tchaikovsky, not a theme that had been composed by someone else in the 18th century.