Christ is often shown seated on thrones that vary in type (lyre-backed, square-backed, or backless). The earliest form of the lyre-backed throne on coins (photo right) may have copied the image of Christ in the conch of the apse above the imperial throne in the Palace. The later form is familiar from mosaics in Hagia Sophia (photo lower right) and from other monuments (see Case III, Nos. 7–9).