The renovation of the decoration
There does not seem to have been any renovation of the early medieval decoration until the 13th century.
The frescoes that were painted on top of the early medieval wall decoration must have appeared after the traumatic earthquake of 1222, though it cannot be excluded that the two lunettes on the north and south walls (Stories from Genesis, Saints) may have been given new paintings before that date. Among the renovated decorations, the oldest fresco is the one with figures of saints (including Magdalene and the allegory of Faith) on the south wall. During the restoration of the building, which is presumed to have been completed by about the middle of the thirteenth century, the frescoes in the presbytery were painted of which there now remain only some fragments (Nativity of Christ, of the mid thirteenth century, in which we can see the scene with the preparation of a baby’s bath). New frescoes were added in the 14th century on the central vault of the presbytery (Christ blessing in Glory, flanked by figures of Saints, on the right, and the scene of the Adoration of the Magi) and on the walls of the main body (Annunciation, Crucifixion), while next to the windows are the Visitation (on the north) and Saints Peter and Paul, holding the sword and the book (on the south). With all probability the fresco decorations ceased with the construction of the wooden stalls of the choir (the oldest in Friuli), dating back to the time of the Abbess Margherita della Torre, before 1384. The choir concealed the whole lower part of the walls of the main body, also partly covering the frescoes painted some decades earlier. Nearly all the painted decorations after the first phase were detached from the walls during modern restoration work, carried out in particular in the Fifties and Sixties of the twentieth century. Part of them were then stored in the sacristy of the Temple, part in the Christian Museum at the cathedral and in the storerooms of the National Archaeological Museum. Also some sculptures placed in the Temple in the Middle Ages have been given new locations: the statue of Calvary placed on the beam supported by the columns that divide the main body from the presbytery area, and the two statues of mourners, on either side of a Crucifix. The works are now kept in the museum of Palazzo de Nordis. A project is being studied for the location of all these elements of great historic and artistic importance in the rooms on the east side of the cloister, in what is to be the Museum of the Monastery and of the Temple. One phase of the medieval renovation of the temple decoration also concerned the outside of the building, on the upper floor where part of the Monastery building was leaning.
In the arches on the façade there are important traces of the fresco decoration that once adorned the outside of the building. On the south arch, to the right of the window, are the remains of a crucifixion with characteristics that have been compared to the early 13th century Byzantine style of the frescoes in the crypt of the basilica at Aquileia.  The decoration in the north arch is better preserved: in the lower part is a first fresco, also dating back to the 13th century, with a praying figure kneeling next to an inscription; above this is a painting of Saint Francis, on the right, receiving the stigmata next to a seraphim and in the presence of another saint. The style recalls German painting of the period and has been placed in the last decades of the 13th century.