In that time, he notated a number of the blind composer's final works, including parts of the Orgelbüchlein. According to Bach's biographer Philipp Spitta, he was present at Bach's deathbed, and took over his duties for nine weeks.
In that time, he transcribed several of the blind composer's last compositions, including sections from the Orgelbüchlein.  According to Bach biographer Philipp Spitta, he was present when Bach died and took on his responsibilities for nine weeks.