Johann Mattheson (September 28, 1681 - April 17, 1764) was a German composer, writer, lexicographer, diplomat and music 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. Wikipedia
The definitive Wikipedia entry for Johann Mattheson. Wikipedia is the biggest multilingual free-content encyclopedia on the Internet. en.wikipedia.org/wiki/Johann_Mattheson