Celtic Tradition.

Baptists have much in common with the ancient Celtic church which came from Ireland to convert the pagan Anglo Saxons after they destroyed the Romano British church left behind by the legions, and prior to the arrival of Augustin's mission from Rome which took over from the Celtic tradition.

This is the triquetra:

The interlaced arcs form a trefoil and is the Celtic symbol for the triune god, Father, Son, and Holy Spirit. The interwoven circle represents the circle of life and in the Celtic tradition references communing with nature and honouring family and friends, important traditions in Celtic Christianity.