Viking Art is remarkably decorative, and is found both as naturalistic as well as more abstract art. Its ornaments require a highly trained eye to be recognized and understood. Most Viking art was applied art, which is to say that it was used mostly for the decoration of objects that were used for practical purposes. Many will recognize similarities between Viking and Celtic designs, which is easily explained by the mutual influences resulting from the Viking settlements and strongholds that existed for several hundred years in many of the Northern British Isles. For a large part of that time the Vikings and Celtics co-existed peacefully and in close proximity to one another. Despite the deep similarities between Viking and Celtic art, however, we also recognize major differences. One of the major differences in style is the asymmetric and restless quality of Viking art, characterized by a seething mass of surface ornament of mostly stylized animals or, more correctly, zoomorphic designs. Contorted and distorted animals had formed the basis of Scandinavian art from the fifth century. This style persisted into and through the Viking age.