This is the opening sinfonia from Bach's cantata BWV 128, a somber and reflective piece often performed independently. Its moving simplicity and profound emotional depth make it a significant work.
Requires sensitive control of dynamics and phrasing to convey the melancholic mood.
Auf Christi Himmelfahrt allein (BWV 128) is rated Henle level 6 of 9 — advanced repertoire, roughly ABRSM grades 7–8. In the RCM system it corresponds to about level 8.
You should be comfortable at Henle level 6 — meaning you can already play level 5–6 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
A typical performance of Auf Christi Himmelfahrt allein (BWV 128) lasts about 10 minutes.
Auf Christi Himmelfahrt allein (BWV 128) is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.