Johann Nikolaus Hanff (1663–1711) was a North German organist and composer. Little is known about his early life. Till 1696 he lived in Hamburg where he was a music teacher. By his own saying, Johann Mattheson was one of them. From 1696 Hanff was organist at the Eutiner Hof of the prince-bishop of Lübeck. After the death of bishop August Friedrich and the dissolution of the Eutiner Hof, probably in 1705, Hanff returned to Hamburg, where his two children were born in 1706 and 1711. On August 26, 1711 he took over the organist chair at the Schleswiger Dom, however he died some months later.
Only a few organ compositions of Hanff survive. Six chorale preludes of Hanff are known today, thanks to copies made by Johann Gottfried Walther. The chorale prelude Auf meinen lieben Gott is transcribed from the Frankberger manuscript, owned by the Nederlands Muziekinstituut.
I made two versions. In one the left hand is notated with the alto-clef. In the other the left hand is notated using the 'modern' treble and bass key. The alto clef is really worth the effort to learn to read: in the so-called modern notation constant clef changes are needed, whereas the alto clef requires none.
The score is available at: http://partitura.org/index.php/johann-nicolaus-hanff-auf-meinen-lieben-gott/