[9] The decoration of the temple is naturally all derived from the Old Testament, but the subjects shown are those believed in the Middle Ages to prefigure the coming of Christ the Messiah.

In the floor tiles David's slaying of Goliath (centre front) foretells Christ's triumph over the devil.

Erwin Panofsky, who developed much of this analysis, proposed a scheme for the significance of the astrological symbols in the round border tiles, and other versions have been suggested.

[13] It has been suggested that Mary has been given the features of Isabella of Portugal, wife of Philip the Good, Duke of Burgundy, who may well have commissioned the painting from van Eyck, his (part-time) court painter.

As is usual, especially in the North, Mary's features are less attractive than those of Gabriel; with his being a sexless angel there was considered to be no possibility of his beauty causing inappropriate thoughts in the onlooker.

Another of van Eyck's themes, and one employed by other Early Netherlandish painters, is indicated by the large cope over a dalmatic worn by Gabriel.

This is certainly to convey the alarm and uncertainty with which she usually greets the surprising apparition of Gabriel and his news, but is also a gesture used by a priest at certain points of a Mass.

[18][19] More generally, this is part of a common theme in Early Netherlandish art where Mary, as intermediary between the faithful and God, is compared to, or seen as, a priest celebrating Mass.

In a surviving extreme example in the Louvre she is shown clearly wearing vestments and celebrating mass at an altar; more often, as here, the comparison is made more subtly.

A cleaning in 1998, and examination by modern technical methods such as infrared reflectograms, has revealed much about van Eyck's technique here, which is consistent with other works of his such as the Arnolfini Portrait.

[23] The play of light over the many different textures in the painting is brilliantly rendered, and the illusionistic detail, especially in Gabriel's rich costume, is exceptional.

The vase of lilies was not only absent in the underdrawing, but was not reserved, that is to say that a space was not left for it in the paint for the Virgin's robe or the floor.

It seems that van Eyck, perhaps acting with clerical advisers – although he appears to have been a considerable reader himself, liked to add further complexity to his compositions in the course of work on them.

Repainted areas included parts of Gabriel's face and hair, and the Virgin's robe, which appeared to have also lost a layer of glaze.

The painting appears stylistically to come between the Ghent Altarpiece and late works such as the Berlin Virgin in a Church.

It is thought that the recent cleaning or technical investigation has tended to confirm the majority view that it is an autograph work by Jan.[30] The provenance of the painting, as far as it is known, is:[31]