Gottfried, Freiherr van Swieten (October 29, 1733 in Leiden – March 29, 1803 in Vienna) was a diplomat, librarian, and government official who served the Austrian Empire during the 18th century. He was an enthusiastic amateur musician and is best remembered today as the patron of several great composers of the Classical era, including Joseph Haydn, Wolfgang Amadeus Mozart, and Ludwig van Beethoven.