Mendelssohn probably began writing his third oratorio in early 1847 based on a libretto by Baron Christian Carl Josias von Bunsen titled “Erde, Hölle und Himmel” (Earth, Hell and Heaven), which is most likely no longer extant. However, his preoccupation with the subject, manifested in verbal drafts, concrete plans and an active search for an appropriate textual basis, can be traced back to 1839, more than seven years before the premiere of “Elijah”, his second oratorio.

There are no written statements by Mendelssohn himself regarding the compositional process. However, reports from his contemporaries prove that the composer was working on the oratorio until a few weeks before his death and that it remained fragmentary. The known autograph score and some sketches are most likely all that the composer left behind in this regard, as there is no evidence of any other musical material for this work ever existing. The individual sketches, which are being prepared with a music-philological approach for the first time in this edition and published accordingly, can all be assigned to the pieces elaborated in the score, except for one (for a German Nunc dimittis). Thus, there are three fully composed movements for the first scene (focusing on the birth of Jesus) as well as the Passion scene with a choral and a chorale movement; all belonging to the first part (“Earth”).

The title “Christus” for the fragment, established by the posthumous first printing of 1852, is based solely on the title handed down by his brother Paul Mendelssohn-Bartholdy via Ignaz Moscheles. As the autograph bears no title, Mendelssohn made no written comments on it, and the content of the underlying libretto is also unknown, we can only speculate whether the composer had already decided on a final title and, if so, what it was. It is also speculative if his third oratorio was intended to be part of a trilogy together with “Paul” and “Elijah”.