Ludwig van Beethoven was a German composer and pianist. A crucial figure in the transition between the Classical and Romantic eras in Western art music, he remains one of the most famous and influential of all composers. His best-known compositions include nine symphonies, five piano concertos, one violin concerto, 32 piano sonatas, 16 string quartets, his great Mass the Missa solemnis, and one opera, Fidelio. Together with Mozart and Haydn, he was part of the First Viennese School. Born in Bonn, then the capital of the Electorate of Cologne and part of the Holy Roman Empire, Beethoven displayed his musical talents at an early age and was taught by his father Johann van Beethoven and by composer and conductor Christian Gottlob Neefe. At the age of 21 he moved to Vienna, where he began studying composition with Joseph Haydn, and gained a reputation as a virtuoso pianist. He lived in Vienna until his death. By his late 20s his hearing began to deteriorate, and by the last decade of his life he was almost totally deaf. In 1811 he gave up conducting and performing in public but continued to compose; many of his most admired works come from these last 15 years of his life.

Wolfgang Amadeus Mozart, whose actual name is Joannes Chrysotomus Wolfgangus Theophilus Mozart, was a composer, pianist, violinist and conductor from the classical period, born in Salzburg. Mozart was a child prodigy. Already competent on keyboard and violin, he composed from the age of five and performed before European royalty. Along with Johann Sebastian Bach and Ludwig van Beethoven, Mozart is considered to be one of the most influential composers of all of music's history. Within the classical tradition, he was able to develop new musical concepts which left an everlasting impression on all the composers that came after him. Together with Joseph Haydn and Ludwig van Beethoven he is part of the First Viennese School. At 17, Mozart was engaged as a musician at the Salzburg court, but grew restless and traveled in search of a better position. From 1763 he traveled with his family through all of Europe for three years and from 1769 he traveled to Italy and France with his father Leopold after which he took residence in Paris. On July 3rd, 1778, his mother passed away and after a short stay in Munich with the Weber family, his father urged him to return to Salzburg, where he was once again hired by the Bishop. While visiting Vienna in 1781, he was dismissed from his Salzburg position. He chose to stay in the capital, where he achieved fame but little financial security. During his final years in Vienna, he composed many of his best-known symphonies, concertos, and operas, and portions of the Requiem, which was largely unfinished at the time of his death.

(Franz) Joseph Haydn was a 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.
He was a friend and mentor of Mozart, a teacher of Beethoven, with whom he formed the First Viennese School. He was also the older brother of composer Michael Haydn.