The mosaic in the Cappella dei Santi Primus e Feliciano depicts the two martyr-saints flanking a jewelled cross. The pair stand in a lush green meadow, which is alive with red roses. The cross culminates in a tondo depicting the head of Christ (a later addition?). At the top of the mosaic, against a background of the firmament, is the hand of God the Father holding a wreath. Below the work is an epigraph recording the dedication of the chapel.