A miniature painting on gilded glass medallion, from Santa Giulia Museum in Brescia, mounted on King Desiderius's Cross.
See more at http://www.hp.uab.edu/image_archive/ulh/painting01.jpg
In the 18th century the medallion was thought to depict a portrait of Galla Placidia with her children. However modern scholars have firmly rejected this identification. https://www.jstor.org/pss/3046553.
Inscriptions on the medallion are not personal names; they have instead been identified as words in the Greek dialect of Alexandria, Egypt, which was then a Roman province.