The style is, interestingly, more Classical than Byzantine especially as regards the main central seated figures of Christ and Our Lady and St Peter on the right of them. At the top of the arch is a cross with the Greek letters Α and Ω (Alpha and Omega), and this is flanked by the Seven Candlesticks of the Book of Revelation. The symbols of the Evangelists are to the left and right, and by the scrolls of the prophets are two cages containing a bird each.

Below this main mosaic is an epigraph, which reads: "This [church is provided] in your honor, outstanding Mother of honour, it shines with the king's splendour of beauty. In which the throne of Christ remains, the seat for eternity. It is fitting to accompany you, since gold has touched it as clothing. When the old edifice was about to fall into ruin, this one was about to rise from it. Innocent, the second pope [of that name] renovated this [church]"