Though his full name was "Franz Joseph Haydn", the name "Franz" was not used in the composer's lifetime, and the use of "Franz" when referencing him is avoided by scholars.
For a work-in-progress attempt to standardize all of Haydn's works, please see http://wiki.musicbrainz.org/CSG_Standard/J_Haydn
Legal name: Franz Joseph Haydn
(Franz) Joseph Haydn (/ˈdʒoʊzəf ˈhaɪdən/; German: [ˈjoːzɛf ˈhaɪdən]; 31 March 1732 – 31 May 1809) was a prominent and prolific Austrian composer of the Classical period. He was instrumental in the development of chamber music such as the piano trio and his contributions to musical form have earned him the epithets "Father of the Symphony" and "Father of the String Quartet".
Haydn spent much of his career as a court musician for the wealthy Esterházy family at their remote estate. Until the later part of his life, this isolated him from other composers and trends in music so that he was, as he put it, "forced to become original". Yet his music circulated widely and for much of his career he was the most celebrated composer in Europe.
Joseph Haydn, a friend and mentor of Mozart, and teacher of Beethoven, was the older brother of composer Michael Haydn.