A composer at nine and soprano in the Hamburg opera at fifteen, Mattheson was known as a person of great talent and intellect. In 1703 he introduced Handel to the musical circles of Hamburg. That same year the two went to Lübeck to consider that city's offer of Buxtehude's post. Unwilling to comply with one stipulation--that he marry Buxtehude's daughter--Mattheson declined the offer. In 1719 Mattheson became deaf. Unable to perform he wrote 88 books before his death, among them Das Beschützte Orchestra (Hamburg, 1717) where, in the earliest printed reference to Bach, Mattheson wrote: "I have seen things by the famous organist of Weimar, Herr Joh. Sebastian Bach, both for the church and for the hand that are certainly such as must make one esteem the man highly." Mattheson's most important book was Der vollkommene Capellmeister (1739).