The third room contains Byzantine and post-Byzantine applied arts of the 6th-18th centuries and West European applied arts of the Middle Ages. The golden necklace with a medallion from the Mersinsky treasure dating from the second half of the 6th century is a unique Byzantine artifact. The agate bowl decorated with gems made in the unique Byzantine technique of striking wire into stone dating from the late 12th - early 13th centuries is remarkable among the Middle Byzantine things.

As a rule West European medieval applied art was anonymous. In the beginning, precious objects to decorate the altars of local churches were created by monks in a monastic scriptorium. For this reason articles for ecclesiastical use predominate among medieval artifacts. Sometimes major feudal lords ordered precious works of art and, to expiate their sins, dedicated them to the church.

Very likely, the figure of the first Christian deacon, St Stephan (Étienne), was one such valuable gift. This was probably a gift of Abbot Étienne of the cathedral of Noyons, who lived at the end of the 12th century. Silver figures like this, which served to keep holy relics, are rather frequently mentioned in inventories of church property but have hardly survived. In this figure we see clear evidence of the basic features of Romanesque style: monumentality, expressiveness and vivid decorative elements. In the saint's face, noble dignity combines with Christian humility, and the exaggerated dimensions of the head and hands holding a book containing relics emphasize the spiritual importance of these holy remains.

Another variety of storage container for holy relics was especially characteristic of the French city of Limoges, where, from the late 13th century, we also note the emergence of secular master jewellers. The brilliance of gilt and the unfading coloration of enamel are organically incorporated into the precious decoration of medieval churches.

In the 13th century, the Gothic style gradually took the ascendant. It was marked by a more realistic treatment of images, by the elongated proportions of figures, and by complex, literally lace-like architectural elements. One of the most celebrated monuments to the High Gothic style is the so-called Freiburg Cross, which came down to us from a monastery near the city of Freiburg on the Upper Rhine. It was made at the end of the 13th century and marks the highest achievement of medieval jewellers.

The predominance of ecclesiastical over secular art continued into the centuries which followed. This is reflected in the choice of objects in the display case: a communion chalice, the figure of the Madonna, a censer, etc. These all date from the 14th-15th centuries and several of them bear the silver marks of urban jewellers, such as the openwork silver cross made in the city of Medina del Campo in Spain. The splendid large monstrance (container for the Consecrated Host) is signed by the master himself, Hans Rissenberg, and dated "1474". It was made in the city of Revel (now Tallinn) for the Church of St Nicholas and later given by the city magistrate to Alexander Menshikov during the Great Northern War between Russia and Sweden (1700-1721). The elegant lancet forms of the monstrance suggest the characteristic features of Late Gothic architecture, but in a more refined and subtle manner.