Johann Mattheson: Allemande aus der Sonate F-Dur op.1 Nr. 2

And here is the 3rd movement from the duet, to which I have added a basso continuo - an allemande.

And here - as promised - another anecdote from Mattheson's life:

Mattheson and Handel applied to succeed Dietrich Buxtehude as organist in Lübeck, but neither eventually accepted. Eventually the post was taken by Johann Christian Schieferdecker, who was willing to marry Buxtehude's eldest daughter, which had been stipulated as a condition. Mattheson and Handel returned to Hamburg, where in 1704 Mattheson was given the post of court master, and soon secretary and correspondent, to the English envoy, a post he held until old age and which assured him a livelihood and elevated social status. He ended his activity as an opera singer the following year and married Catharina Jennings, an English pastor's daughter, in 1709; the marriage remained childless.