|Born||28 September 1681
|Died||17 April 1764 (aged 82)
|Occupation||German composer and theorist|
Mattheson was born and died in Hamburg. He was a close friend of George Frideric Handel, although he nearly killed him in a sudden quarrel, during a performance of Mattheson's opera Cleopatra in 1704. Handel was saved only by a large button which turned aside Mattheson's sword. The two were afterwards reconciled, and, shortly after his friend's death, Mattheson even would translate himself into German John Mainwaring's Handel biography and have it published at his expense ("auf Kosten des Übersetzers") in 1761, in Hamburgh, under the title: Georg Friderich Händels Lebensbeschreibung, nebst einem Verzeichnisse seiner Ausübungswerke und deren Beurtheilung; übersetzet, auch mit einigen Anmerkungen, absonderlich über den hamburgischen Artikel, versehen vom Legations-Rath Mattheson. 
The son of a well-to-do tax collector, Mattheson received a broad liberal education and, aside from general musical training, took lessons in keyboard instruments, violin, composition and singing. By age nine he was singing and playing organ in church and was a member of the chorus of the Hamburg opera. He made his solo debut with the Hamburg opera in 1696 in female roles and, after his voice changed, sang tenor at the opera, conducted rehearsals and composed operas himself. He was cantor at St. Mary's Cathedral from 1718 until increasing deafness led to his retirement from that post in 1728.
Mattheson's chief occupation from 1706 was as a professional diplomat. He had studied English in school and spoke it fluently. He became tutor to the son of the English ambassador Sir John Wich and then secretary to the ambassador. He went on diplomatic missions abroad representing the ambassador. In 1709 he married an English woman.
After his death in 1764, Johann Mattheson was buried in the vault of Hamburg's St. Michaelis' Church where his grave can be visited.
Mattheson is mainly famous as a music theorist. He was the most abundant writer on performance practice, theatrical style, and harmony of the German Baroque. In addition to some original work—particularly on the relationship of the disciplines of rhetoric and music—he was a compiler of most of the ideas current at the time. His books raise more and more attention and suspicion because Mattheson was a brilliant polemist and his theories on music are often full of pedantry and pseudo-erudition.
The bulk of his compositional output was vocal, including eight operas, and numerous oratorios and cantatas. He also wrote a few sonatas and some keyboard music, including pieces meant for keyboard instruction. All of his music, except for one opera, one oratorio, and a few collections of instrumental music, went missing with the spoils of war after World War II, but was given back to Hamburg by Yerevan, in Armenia, in 1998. This includes four operas and most of the oratorios. The manuscripts are now located at the Staats- und Universitätsbibliothek Hamburg, the former Hamburg Stadtbibliothek (City Library).
- Accessible for free online as a Google ebook.
- Agathe Sueur, Le Frein et l'Aiguillon. Eloquence musicale et nombre oratoire (XVIe-XVIIIe siècle), Paris, Classiques Garnier, 2014.
- "Johann Mattheson", "Rhetoric and music" from The New Grove Dictionary of Music and Musicians, ed. Stanley Sadie. 20 vol. London, Macmillan Publishers Ltd., 1980. ISBN 1-56159-174-2
- Manfred Bukofzer, Music in the Baroque Era. New York, W.W. Norton & Co., 1947. ISBN 0-393-09745-5