"The Annunciation Triptych" displays the hallmarks of the emergent Early Netherlandish style. A fascination with the natural world dominates. The smallest details are meticulously worked to reflect reality on a two-dimensional plane. Illusionistic effects are enhanced by the technical innovation of overlaying translucent oil pigments on aqueous opaque pigments. The resulting luminous, enamel-like surface achieves apparent depth, rich gradations of light, and a broad distribution of color values.

"The Annunciation Triptych" was conceived as an object of private devotion. Although scholars have given complex interpretations for its iconography, the significance of the imagery must have been understood by the ordinary educated person of its time. The center panel focuses on the Virgin in prayer. As she has not yet recognized the presence of the archangel Gabriel, the event depicted is the moment just before the Annunciation. Some objects, such as the lily and the laver, symbolize the Virgin's purity expressed through the divine birth of Christ. The tiny figure of the Christ Child bearing a cross and descending on rays of light from the round window indicates that the primary subject is the Incarnation. This understanding is borne out by the flame of the candle, symbolic of God's divinity, which has just been extinguished, a further reference to the Incarnation, the moment when God became man. This significant detail is placed in the exact center of the composition.

The presence on the right panel of Joseph, who is not usually attendant at the Annunciation, can also be explained in the context of the Incarnation. Joseph has made two mousetraps, whose meaning is elucidated by the Augustinian speculation that the Incarnation was God's means of ensnaring the devil, much as bait entraps a mouse.

The coat of arms depicted in the left window transom in the central panel has been identified as that of the Ingelbrechts of Malines, who are documented in Tournai in 1427. The donatrix and the messenger in the background of the left panel may have been added at a later date, presumably after the donor's marriage.

Marking: Arms (central panel, left window): D'or au chevron de sable charge sur sa pointe d'une chaine de quatre chainons d'argent elle meme placee en chevron. For Ingelbrechts (Inghelbrechts or Ymbrechts) of Nalines and Spain. Arms (central panel, right window): D'or a la fasce de gueules accolee de trois annelets de meme. Possibly for Calcum (Lohausen) family, Germany. Arms on shield of figure behind the donors): D'or aux trois pals de gueles.

Prince Pierre d'Arenberg (1820?-) ; comtesse Marie de Merode ; comtesse Jeanne de Merode , Westerloo-Tongerloo and Brussels (by 1877-) ; [ Rosenberg & Stiebel , New York (until 1956)]