Insular Art is an area within medieval studies that specializes in the analysis of artifacts, particularly those created in between the years 600-900 of the common era in the British Isles, Ireland, and the Isle of Man (throughout the Viking period).
It is not to be confused with Anglo Saxon art, as the latter is often considered past the 9th century, although there is still debate among scholars as to where the Insular period ends, and the Anglo Saxon begins.
This artistic style denotes themes of the abstract, lines, and forms of rythmic patterns and trends. You can find illuminated manuscript, a vast use of color, and the use of iron and other metals with powerful thematic that much resembles Islamic and other Eastern art.
The example in this answer shows the famous Crux Gemmata (encrusted cross) which displays
2.Gaelic Isles thematics
4. Deeply rich colors
5. Linear patterns