Aaron’s rod which bloomed without roots or water, was likened to the Virgin by all four Doctors of the Western Church. Virga is the Latin word with which Jerome translated the Hebrew matteh, and the poetic effects offered by the linguistic similarities of virga and virgo were seized upon by countless other interpreters of the Scriptures through the ages.
The inscribed rectangle in the middle of the central panel of this fifteenth-century altarpiece shows the Madonna and Child enthroned surrounded by symbols of Christ and scenes and figures from the Old Testament. The preponderance of inscriptions leaves little doubt as to the painting’s didactic function, and the inscription on the lower part of the engaged frame, underwriting all the rest, proclaims its overall theme: Hanc per figuram noscas castam parituram (‘Learn of the Virgin birth through this painting’). It is clear from the many vignettes, both textual and figural, that the Virgin birth is to be understood not only as the miraculous conception of Christ, but also the perpetual virginity of Mary. Saints Jerome and Augustine, both of whom wrote treatises in defence of this doctrine, appear in the wings of the altarpiece holding scrolls which proclaim it.
Despite this focus on Mary’s purity, Christ is also foregrounded in the imagery. Four triangles surrounding the Madonna contain symbols relating to his Passion and Resurrection—the pelican who pierces her breast to feed her chicks, the lioness whose cubs awake on the third day, the phoenix who rises again, and the unicorn tamed by a virgin.
These scenes are encased within a quatrefoil of four semi-circles containing scenes from the Old Testament. Aaron appears in the upper right, kneeling before the altar, his gaze trained upon his budding rod. As with the altarpiece’s overall imagery, the depiction of Aaron proclaims the miracle of the Virgin birth while also celebrating Christ, the fruit of her miraculous fecundity.
The inscription Hec contra morem produxit virgula florem stresses the parity between the rod and the Virgin’s womb.
Das Rheinische Landesmuseum. 1977. Auswahlskatalog 4: Kunst und Kunsthandwerk: Mittelalter und Neuzeit (Bonn: Rheinland-Verlag), pp. 53–58