Triquetra / Trinity Knot

There is no definitive Celtic family symbol, but there are several ancient Celtic knots that represent eternal love, strength, and family unity.

Triquetra considered the oldest symbol of spirituality. He is depicted in the 9th century Book of Kells and also appears in 11th century Norse stave churches. 

Difficult triquetra, also known as Trinity knot or the Celtic triangle, is one of the most beautiful Celtic symbols and is a circle intertwined with a continuous three-pointed symbol.