The mosaic that adorns the facade of Santa Maria in Trastevere probably dates back to the 12th century. Its meaning has long been a puzzle.
Madonna Lactans
In the centre of the mosaic sits the Virgin Mary suckling the Christ Child, a type of image known as the Madonna Lactans. At the base of her throne kneel two tiny figures, whose tonsured heads indicate an ecclesiastical background.
Mary is flanked by ten female figures. Eight of the ten are crowned and clad in royal regalia, while the two to the Virgin's left do not wear crowns and are more simply dressed. All ten figures have halos and are carrying lamps, but the lamps of the two uncrowned figures are unlit! The iconography of this scene is unique and its significance unclear. The mosaic was once thought to illustrate the story of the Wise and Foolish Virgins, but this is now disputed.
Nave
Most of the mosaics in the apse of the church also date back to the 12th century, specifically to the reign of Pope Innocent II (r. 1130-43).
In the conch of the apse, sitting side by side on the same throne, are the Virgin Mary and Christ.
The Virgin Mary and Christ
Christ has placed his right hand on Mary's shoulder, and with his left holds an open book, which reads: VENI ELECTA MEA ET PONAM IN TE THRONUM MEUM (Come, my chosen one, I will place you on my throne). Mary displays a band on which is written: LEVA EIVS SVB CAPITE MEO ET DEX[T]ERA ILLIVS AMPLESABIT[UR) ME (His left hand is under my head, and his right hand doth embrace me), which is a quotation from the Song of Solomon (2:6). At the same time, Mary points to Christ with two fingers of her left hand.
Hand of God
The Hand of God (Dexter Dei) holds a wreath above Christ's head.
Pope Innocent II & St Lawrence
On the left of Mary and Christ stand Pope Innocent II (holding a model of the church), St Lawrence and Pope St Callixtus, while on the right stand St Peter, Pope St Cornelius, Pope St Julius and St Calepodius.
Prophet Isaiah
The apsidal arch depicts, in addition to the symbols of the four Evangelists, two Old Testament prophets, Isaiah and Jeremiah. Each prophet holds a scroll. That of Isaiah proclaims: ECCE VIRGO CONCIPIET ET PARIET FILIVM(Behold, a virgin will conceive and give birth to a Son) and that of Jeremiah: XPC DNS CAPTVS E IN PECCATIS NRIS (Christ the Lord is caught in our sins).
Prophet Jeremiah
Above each prophet is a small caged bird, a curious image the meaning of which is a puzzle. Does the answer lie in the words on Jeremiah's scroll? At the top of the arch there is a cross, with the Greek letters A and Ω (Alpha and Omega), which is flanked by the Seven Candlesticks of the Book of Revelation.
At a lower level are six mosaics (c. 1291) depicting scenes from the life of the Virgin Mary, the work of the Roman painter and mosaicist Pietro Cavallini (c.1250-c.1330).
The Dormition
From left to right: TheBirth of Mary, TheAnnunciation, TheNativity, The Adoration of the Magi, ThePresentation in the Temple and TheDormition.
Virgin and Child, St Peter and St Paul, and Cardinal Bertoldo Stefaneschi
The mosaics were commissioned by Cardinal Bertoldo Stefaneschi, who is depicted kneeling in the presence of the Virgin and Child, St Peter and St Paul.