"Herr Christ, der einig Gotts Sohn" is one of the earliest Lutheran chorales. Written by Elisabeth Cruciger (née von Meseritz; c. 1500–1535), a former nun who was won over for the Lutheran Reformation and moved to Wittenberg, where she married Caspar Cruciger in 1524, it was included in both printings of the “Erfurt Enchiridion,” as well as Johann Walter’s Wittenberg Geystliche gesangk Buchleyn of the same year.
Though the hymn has come to be associated with Christmas and Epiphany due to some stanzas’ emphasis on the Incarnation and on Jesus as the “Morning Star,” in the Erfurt Enchiridion it was entitled “A Song of Praise Concerning Christ” and was not included among the hymns ordered according to the Church Year. In later hymnals it was included in the section on Faith and Justification, and has been thus categorized at the Free Lutheran Chorale-Book.
A scan of the hymn in the Loersfeld printing of the “Erfurt Enchiridion” can find it in the attachment.