From Constantine to Justinian : A marble relief of the Theodosian period.--On the interpretation of stylistic changes in late antique art.--Mosaic pavements in the Greek East and the question of a "Renaissance" under Justinian.--Stylistic developments in pavement mosaics in the Greek East from the age of Constantine to the age of Justinian.--From Justinian to iconoclasm : The cult of images in the age before iconoclasm.--Byzantine art in the period between Justinian and iconoclasm.--On some icons of the seventh century.--Some reflections on portraiture in Byzantine art.--Byzantium and the Medieval West : The first mosaic decoration of Salerno cathedral.--The mosaics of the Cappella Palalina in Palermo.--On the portrait of Roger II in the Martorana in Palermo.--World map and fortune's wheel; a medieval mosaic floor in Turin.--The Byzantine contribution to western art of the twelfth and thirteenth centuries.