Gospel Cover of Eribertus
Milan, Treasury of the Duomo
Above the upper register and below the lower, the inscription says Eribertus Archiepiscopus Sancta[e] Mediolanensis Ecclesiae, "Archbishop Eribertus of the Holy Church of Milan."
In the upper register the Archbishop is represented as the small figure being presented by John the Evangelist to Christ, whose left hand holds a banner inscribed Lex et Pax, "Law and Peace." John and the Virgin are also identified by the inscriptions to the left and right of the upper register.
The figures in the lower register are labeled (left to right), Sanctus Prothasiu[s], Sanctus Ambrosius, and Sanctus Gervasius (see Golden Legend #85, html or pdf).
More of St. Ambrose
More of SS. Gervase and Protasius
Source: Thais – Scultura Italiana