 Interesting developments in the artistic use of interlaced knot patterns are found in Byzantine architecture and book illumination, Coptic art, Celtic art, Islamic art, Kievan Rus'ian book illumination, Ethiopian art, and European architecture and book illumination.Spirals, step patterns, and key patterns are dominant motifs in Celtic art before the Christian influence on the Celts, which began around 450.These designs found their way into early Christian manuscripts and artwork with the addition of depictions from life, such as animals, plants and even humans.