Rex et Legifer noster
"O Emmanuel, our king and lawgiver, long-awaited Saviour of the nations, come to save us, O Lord our God."
- Magnificat antiphon for 23 December.
The apse mosaic of Sta Pudenziana in Rome dates to c.390, and is the oldest extant example of such decoration in Rome. As usual, Christ is flanked by St Peter (on the right) and St Paul, crowned by personifications of the Church of the Gentiles (on the left) and the Church of the Jews. Christ is enthroned in the centre, in one of the earliest portrayals of the Jesus Christ as Emmanuel, God-with-us, in the flesh. As if to underline this, St Paul holds a book with the opening words of St Matthew's gospel: "Liber generationis", the book of the genealogy of Jesus Christ.
With his right hand pointed in blessing, and with a book in his left hand, Christ is shown in a convention of Roman imperial art of the so-called traditio legis, or the handing down of the law. Around him his disciples are gathered in senatorial garb. Hence, Christ is shown as both Ruler and Law-Giver. The book he holds bears an inscription describing himself as 'Lord and Protector of the Church of Pudenziana'.