From bottom to top, the altarpiece consists of a predella, a central section flanked by two figures on consoles and a top section with a lacelike openwork crown. It is placed on a low stepped pedestal, slightly wider than the predella. The predella is decorated with a shallow relief of St Margaret with a dragon and St Barbara holding a chalice; the former points with her left hand to the attribute of the latter. The sides of the predella are decorated by two heads of herms, which help to support the thin-profiled predella, on which rests the central section of the altarpiece, delimited above by an arched frame. The lower half features a high relief figural group showing the Annunciation: on the left is an angel with hands crossed over its chest and on the right is Mary with hands folded in prayer and resting on her belly. The Virgin is seated on a throne; the figures are separated by a lectern with a book and the scene is crowned with an arched frieze. Above them is the Child of God surrounded by a halo of rays and a roundel of clouds. The central section is flanked by two mannerist elongated figures with mournful expressions and noticeably small heads – on the left is Mary and on the right John the Evangelist. The latter looks up to the image of God the Father in the top section, again rendered in shallow relief: his right hand is raised in blessing and his left rests on an orb. A cross wrapped in thorns forms the central motif of the openwork crown, a fantastical weave of ornate ironwork curls and swirls. The motif of thorns is repeated in the predella with the two saints. 

The strong upward thrust, the console figures of distinctly mannerist proportions, the lacelike ornamentation of the altarpiece crown, the volute motifs on the sides of the central section and the small decorative arrays (ovoid and bar-shaped motifs in several variations and a diamond motif) that adorn the frame of the central section of this  altarpiece, the composition of which is completely dematerialised, suggest that this is a late 17th-century work.