Composers of the Classical music period started writing cello parts which had an identity of their own. Joseph Haydn (1732-1809) wrote 68 string quartets, and made it a very popular form. His quartets from opus 33 were, he said, “written in a new and special way”. All four parts were very clear and individual. There were always four movements: a fast movement, a slow one, a Minuet and Trio and a fast final movement. Haydn often played in a quartet with Wolfgang Amadeus Mozart (1756-1791) and two other players. Mozart also wrote 23 string quartets and dedicated some of them to Haydn. Three of Mozart’s later ones were written for the King of Prussia who played the cello well, so Mozart gave the cello lots of difficult music to play.