Barbarians in fantasy paintings often wear ornate bronze jewelry or carry ornamental weapons.
(Tara Brooch, front view, early 8th century)
There’s a historical basis for such a decorative style. “Migration period art” is a term describes the ornate style of various cultures in the period between 300 and 900 AD after Rome fell and before the Church consolidated its power in the Middle Ages.
(Gundestrup cauldron, Denmark)
These roving groups included Huns, Angles, Saxons, Celts, Visigoths, Vikings and Jutes. Instead of lavishing their artistry on large permanent architecture or monumental sculptures, they created mostly portable works on carved stone and hammered metal.
Many of the design devices of Celtic illuminated manuscripts borrow design motifs such as spirals and scrolls, which were originally part of the metalworking tradition.
(Sutton Hoo purse lid)
People were often buried with such goods to help them in their afterlife journey, until Christianity changed the practice.
Migration Period Art on Wikipedia
Staffordshire Hoard on Wikipedia
Arts of the Migration Period in the Walters Art Gallery Hunnish, Gothic, Ostrogothic, Frankish, Burgundian, Langobard, Visigothic, Avaric, Irish and Viking
The Fall of Rome and the Art of the Migration Period