Circle A circle is an endless line, having no beginning and no end, which symbolises eternity or God. Three entwined circles represent the Trinity, with its three eternal and unified members.
Borromean Rings According to the Athanasian Creed we worship one God in Trinity, and Trinity in unity and so Borromean rings have been used to represent this idea. An association can be traced back to Saint Augustin of Hippo (354-430). He described how three gold rings could be three rings but of one substance. A now lost 13th century French manuscript described the word "unitas" at the intersection of all rings and the three syllables of "tri-ni-tas" distributed in the outer sectors.
Triangle An equilateral triangle having all sides of equal length and each angle equal represents one God in three Persons. This is probably one of the earliest symbolic representations of the Trinity.
Trefoil This is a single design composed of three joined circles. It is believed to be a stylised shamrock which St Patrick used to illustrate the doctrine of the Trinity. It signifies one God in three Persons.
Triquetra An early Trinitarian design found especially in Great Britain, its three equal arcs represent equality, its continuous line expresses eternity, and the interweaving represents indivisibility. It is suggested that the design is based on the sign of the fish known to be used by early Christians.
Fleur-de-lis A stylised lily, or iris, which represents several ideas, purity – hence the Virgin Mary (one tradition claims it is the representation of the tears shed by the mother of Jesus at his crucifixion), royalty because it was adopted by the French kings and the Trinity because of its three part shape.
Fish Which is believed to be the first early Christian symbol is taken a stage further by combining three fish within a basic triangular shape. Each letter for "fish" (IXOYG) represented a key word related to the identity of Christ. He was "Jesus Christ (IX), Son of God (OY), Saviour (G)."
Scutum Fidei or the Shield of the Trinity This is described as “a traditional Christian visual symbol which expresses many aspects of the doctrine of the Trinity (summarising the first part of the Athanasian Creed) in a compact diagram. In medieval England and France this emblem was considered to be the heraldic arms of God (or of the Trinity).” The shield consists of four circles. The three outer containing the words Father (Pater), Son (Filius) and Holy Spirit (Spiritus Sanctus). The centre circle contains the word God (Deus). The outer links contain the words “is not” (non est), whilst the inner links contain the word “is” (est). The links are non-directional.