"In the centre of the triumphal arch mosaic, Christ appears looking angry and holding the rod of iron with which he is to 'rule all nations' (Revelations 12:5)."
"Usually this style of mosaic has Christ at the centre with saints either side, whereas here Saint Agnes takes centre stage, with the flames of her martyrdom at her feet."
"Christ and his mother sit enthroned in the circle which represents the Universe, beyond is the gold sky and angels of Heaven."
"The apse mosaic is filled with characters from the book of Revelations, down to the Tree of Life indicated by the phoenix sitting in it's branches."
"The earliest surviving mosaic representation of the Second Coming in Rome, forerunner of all later versions. This was commissioned by Felix IV in the 530s."
"This very early circular building has two apses, with Christ in his two aspects as God, ruling over the Universe and distributing the law, and as the Son who commands his apostles to spread his word."