These mosaics belong to very various dates.
Apart from the illuminated MSS., the mural paintings, the mosaics, and the goldsmith's work of Mount Athos are of infinite interest to the student of Byzantine art.
Two side niches contain the earliest known mosaics of distinctively Christian subjects.
Satiro are even earlier mosaics (5th century); there are also fine frescoes by Borgognone and Bernardino Lanini.
The richness of effect which the English or French architect obtained by elaborate and carefully worked mouldings was produced in Italy by the beauty of polished marbles and jewel-like mosaics - the details being mostly rather coarse and often carelessly executed.