Between to the 6th to the 11th centuries AC. Is called The Dark Ages. In this time, Art was alive mainly in the monasteries. In the 5th century AD. barbarian tribes from northern and central Europe wandered over the continent.
These people produced very strong pattern on his art. They were dabbler in designs of dragons and birds.
The best of Celtic and Saxon art is found in manuscripts of the 7th and 8th centuries. Book illumination and miniature painting, practiced since late Roman times, increased in the middle Ages.
Gold, silver and bright colors were used. Very little wall painting survives from the middle Ages. There were several great series of frescoes painted in churches built during the Romanesque period (11th-13th centuries). But most of them have disappeared.
A page from an Italian manuscript shows elaborately decorated initials and a finely detailed marginal scene of Saint George slaying the dragon. The colors are brilliant and jewel-like, as in stained glass, and gold shimmers over the page. . Artists probably used magnifying glasses to do such intricate work.
From Wikipedia http://en.wikipedia.org/wiki/file:Codex_Aureus_Sankt_Emmeram.jpg