The area of the apse of the smaller, pre-Euphrasian basilica was used as the sacristy until the early 21st century. The apse floor was adorned by the polychrome mosaic which is best preserved in the western part of the area, where it follows the semi-circular wall, the remnant of the stone bench for the clergy. In the 18th century, a large tomb was installed in the area. In the early Middle Ages, probably in the 8th century, a stone sarcophagus was placed in its southwest corner, with an arcosolium – a vaulted tomb in a wall recess – erected above it. These elements ended up underground in the 9th or 10th century, when the floor level of the entire area was raised and the room was turned into a small chapel by adding three semicircular apses. Today, only their excavated foundations are visible, since they were dismantled in the 14th century, when the room, once again receiving its original rectangular layout, was turned into a sacristy with fresco-decorated walls, parts of which have been poorly preserved on three of the walls. On the southern wall, one can discern episodes from the Passion of Christ: Christ’s arrest and Christ before Pilates. A somewhat better preserved scene on the northern wall shows quite clearly two executioners flogging a person fallen to his knees. So far, the saint whose torturing is shown has not been identified with certainty. On the same wall, another fragment of a fresco has been preserved, looking to the left from the semi-circular window. It is clear that this fresco lies in the layer beneath the Gothic paintings. This is a remnant of the oldest wall paintings, dating from the time before the 9th century.