The so-called "Pax of Ariberto" was created around 1030 or 1040 and given to the Duomo by Archbishop Ariberto. It consists of two panels - the more elaborate one was used to decorate the box in which the cathedral's Gospel book was kept, while the other covered the Gospel book itself. In the 12th century it became part of a "Pax," a panel with a handle that was presented during the ritual of the kiss of peace.
The main panel is covered in gold and decorated with enamel and precious stones. In the center is a crucifix against a backdrop of deep green, with the words LUXMUNDI ("Light of the World") above the head of Christ. In this representation Christ is shown dead, with his head bowed and eyes closed.
Flanking the cross as usual are the Virgin Mary and St. John as well as two soldiers with spears. The enamel panel above the crucifix shows the Ascension of Christ, observed by the Twelve Apostles in two separate panels. The four corners have medallions with the symbols of the Evangelists. Two smaller medallions at the top have busts of uncertain (to me) persons.
The panel to the left of the cross shows a women at the empty tomb, greeted by an angel, while the panel to the right shows the Good Thief being led into Paradise by Christ. Below the cross is the Harrowing of Hell, flanked by St. Ambrose (left) and his brother St. Satirus (right).