Johann Georg Albrechtsberger (3 February 1736 – 7 March 1809) was an Austrian composer, organist, and music theorist, and one of the teachers of Ludwig van Beethoven. He was friendly with Haydn and Mozart.Albrechtsberger was born at Klosterneuburg, near Vienna. He originally studied music at Melk Abbey and philosophy at a Benedictine seminary in Vienna, and became one of the most learned and skillful contrapuntists of his age. Albrechtsberger's earliest classmates included Michael Haydn and Franz Joseph Aumann. After being employed as organist at Raab in 1755 and Maria Taferl in 1757, he was appointed Thurnermeister back at Melk Abbey. In 1772 he was appointed organist to the court of Vienna, and in 1792 Kapellmeister of St. Stephen's Cathedral.