Here is something marvelous I stumbled across on Wikipedia, a frescoed medieval oratory in the village of Bominaco in the Abruzzo region of Italy, about 64 miles to the east-northeast of Rome. It was built in 1263 as part of a Benedictine monastic complex originally founded in the Carolingian era. Although the exterior is about as plain as it gets, the interior is covered with fresco work which is in remarkably good condition, especially considering its age. The Saint to whom it is dedicated is a local martyr of whom very little is known.
Here are general two views of the frescoes; detailed images with descriptions are given below. (All images from
this page of Wikimedia Commons, by Pietro,
CC BY-SA 3.0, except the last two.)
The front of the oratory...
and the back.
The date of the oratory’s foundation and the name of the reigning abbot, Teodino, are given in this inscription over the window.

The left side of the counterfaçade is dominated by a picture of St Christopher. In accordance with the popular belief that if one saw an image of him, one would suffer no sudden misfortune that day, images of him were often made very large, which in turn created the tradition that he was a giant. Around, going clockwise from under the window, are the prophet Zachariah, holding a banderole on which is written, “Behold thy king shall come unto thee” (9, 9), in reference to the picture next to it of the Lord’s triumphal entry into Jerusalem; the prophet Isaiah, holding a banderole on which is written, “Be washed be ye clean”, in reference to the picture next to it of the Lord washing the disciples’ feet at the Last Supper; St Onuphrius, and the Saint Francis of Assisi. At the top of the right side, as part of a cycle of episodes of Our Lord’s infancy, the Massacre of the Innocents.
.jpg)
To the right of the picture of above (when facing it): in the lower register, the punishments of the damned. In the register above it, episodes of the Passion: Judas speaking to the priest and receiving his thirty pieces of silver; the betrayal in the garden; Christ before Pilate.
On the opposite wall, the rewards of the just in the lower register; in the upper, the Passion cycle continues with the flagellation at the column, the removal of the Lord’s body from the cross, and the entombment.
In the highest register, to the right of the
counterfaçade (facing), the Annunciation and the Visitation; below, the Last Supper.
On the opposite wall, the adoration of the Magi, and Herod giving instructions to his soldiers.
In the second bay of the building (i.e. closer to the altar) in the upper register are depicted the Birth of Christ (with His first bath at the lower left), and the appearance of the angel to the shepherds; below these, episodes from the life of St Pellegrino.
On the opposite wall are the journey of the Magi (right) and the Presentation in the temple (left); the stories in the lower register are obviously very badly damaged.
In the third bay are depicted the appearance of the Lord to the disciples on the road to Emmaus; on the left side, He appears dressed as a pilgrim, referring to the words of the two disciples, “Art thou the only sojourner (peregrinus) in Jerusalem that knoweth not the things that have happened therein in these days?” (Luke 24, 18.) In the middle, the Lord appears more like Himself, and the two disciples are labelled, Cleopas and Luke. On the right, St Martin divides his cloak for the beggar.
The same bay is also decorated with a liturgical calendar, in which each months is depicted by a figure doing something characteristic of the period (in January, someone warms himself at a fire), and then a panel with the sign of the zodiac, and a list of feast days. In the upper part are depicted figures from the Old Testament; on this side, Moses, Job, Jonah and Isaiah...
and on the opposite side, Adam, Daniel, Samuel, Solomon, and Elijah.
These carved marble plutei separate the very back of the church from the rest of it, one decorated with a sea monster...
and the other with a griffin. (Both images from the same Wikimedia Commons page, by Kewerner,
CC BY-SA 4.0.)