The Shield Knot is an ancient Celtic symbol of protection and was placed either on battle fields to protect soldiers from physical and spiritual harm, or near the sick as a means of warding off evil spirits or other threats.
However, like many knot symbols, the Celtic Shield Knot was also seen to symbolise faith, love and unity between people. This appears to be the more modern use for the knot, appearing on wedding bands and jewellery gifts between loved ones.
Interwoven patterns, like these knots, were first seen in the crafts of the Roman Empire. In the third and fourth centuries AD, knot patterns were first seen, mainly as an art form that was soon adapted to mosaic floor patterns too. This art form was used a lot in Byzantine architecture, Celtic art, Coptic art, Islamic art, and many more forms.