1. Oxford, Bodleian Library Bodley 739 (SC 2736): HG 593.
2. Oxford, Bodleian Library Bodley 827 (SC 2718): HG 605.
3. Salisbury, Cathedral Library 140: HG 739.

1. Incar.sacram.VI.27-29: ALCVIN.Adu.Fel.218.59-219.2.
2. Incar.sacram.VI.21-26: ALCVIN.Adu.Fel.219.6-12.
3. Incar.sacram.VIII.65-68: ALCVIN.Epist.Episc.Franc.144.21-22.
4. Incar.sacram.VIII.66: ALCVIN.Adu.Elipand.261.51-52.
5. Incar.sacram.V.7-10: ALCVIN.Adu.Elipand.280.52-55.
6. Incar.sacram.V.15-18: ALCVIN.Adu.Elipand.280.55-281.2.

In this work Ambrose first discusses the sacrifices of Cain and Abel, identifying Cain with heretics; he then discusses the Incarnation, refuting the Apollinarian heresy. The concluding section of the work answers certain objections raised by two Arian chamberlains of the emperor Gratian concerning the single nature of the "unborn" (ingenitus) Christ. The work was often appended as a ninth book to the five books of DE FIDE and the three books of DE SPIRITU SANCTO (see Wallach 1977 p 124). In his ADVERSUS FELICEM (PL 101), ALCUIN cites the work as part of De fide.

The three English manuscripts of the work are all post-Conquest. For the Salisbury manuscript, see Webber 1992 (p 152). For the textual relationship of the two Oxford manuscripts, see the entry for De fide.

In the Epistola Episcoporum Franciae ascribed to Alcuin, he accuses Elipandus of Toledo of having altered a quotation from De incarnationis dominicae sacramento to support the Adoptionist heresy (MGH CAC 144.21-22). In this work Alcuin inexplicably attributes the quotation to HILARY OF POITIERS, despite the fact that Elipandus in his Epistola Episcoporum Hispaniae (MGH CAC 2.112.11-13) had identified it as from "Ambrosius in libro de trinitate." Later (in ADVERSUS ELIPANDUM II.v; PL 101.280.48), responding to Elipandus's Epistola ad Albinum (MGH ECA 2.303.23-24), he corrects the attribution, and cites the work again as "De incarnatione Christi", this time by way of PAULINUS OF AQUILEIA, Contra Felicem III.xxi.27-33; CCCM 95; see C. Wright 1998 p 163).