Shield of the Trinity

The Shield of the Trinity diagram is attested from as early as a c. 1208–1216 manuscript of Peter of Poitiers' Compendium Historiae in Genealogia Christi.

The c. 1260 allegorical illustrations of a knight battling the seven deadly sins in a manuscript of William Peraldus' Summa Vitiorum, and of a woman penitent fending off diabolical attacks in the De Quincy Apocalypse, show the diagram placed on a shield.

The only name for this diagram which was in any regular use during the Middle Ages was "Scutum Fidei", a Latin phrase meaning "Shield of the Faith", taken from the Vulgate of Ephesians verse 6:16.

This coat of arms was given the following heraldic blazon in "On Sacred Heraldry" by E.L. Blackburne, attached as Appendix II to Emblems of the Saints, By which they are Distinguished in Works of Art by F. C. Husenbeth, edited by Augustus Jessopp, 3rd.ed.

1882: The diagram on a blue shield (heraldic "azure") was the coat of arms of the Priory of Black Canons (monastery of Christ Church) near Aldgate in the City of London.

Two of the 13th-century manuscripts have the diagram on a green shield (heraldic "vert"), which is also found in the coat of arms of Trinity Parish, Jersey shown below.

In the Middle Ages, the shield-shaped version of the diagram was sometimes imagined as a protective shield wielded by the Archangel Michael, or by an ordinary soul, in the spiritual warfare against dark forces described in Ephesians chapter 6, as in the c. 1260 allegorical illustrations in manuscripts of Peraldus' Summa Vitiorum and the De Quincy Apocalypse.

A symmetrical rounded form of the diagram with one vertex up and two down was popularized in the modern period by the Audsleys' Handbook of Christian Symbolism.

Many further slight artistic variations can occur in the relative sizes of nodes and links, their exact placement, in lettering styles, in further decorative elaboration, etc.

This is similar to the version of the Shield of the Trinity present in a 15th-century stained glass window in St. Peter and St. Paul church, Fressingfield, Suffolk, England, where only the positive or asserting parts of the diagram are shown—see link below.

The placement of the captions "FILIUS" or Son and "SPIRITUS SANCTUS" or Holy Spirit in the remaining two outer nodes can vary.

The diagram below shows the earliest and most recent major variants of the "Shield of the Trinity" diagram: On the left, the form attested in various manuscripts c. 1208–1260 AD, and on the right the form popularized among some English-speaking Protestants in recent years by Paul P. Enns' 1989 book The Moody Handbook of Theology and H. Wayne House's 1992 book Charts of Christian Theology and Doctrine.

Basic "Shield of the Trinity" diagram
The earliest attested version of the diagram, from a manuscript of Peter of Poitiers ' writings, c. 1210.
Petrus Alfonsi 's early 12th-century Tetragrammaton -Trinity diagram, a probable precursor to the Shield of the Trinity.
From William Peraldus ' Summa Vitiorum , c. 1255–1265. Includes e converso ("vice versa") in the link captions to clarify that links are bidirectional.
Four variants of the "Shield of the Trinity"
An 1833 reconstruction of the Agincourt banner of the Trinity
The earliest and most recent major variations of the "Shield of the Trinity" diagram.
Arms attributed to St. Michael in the 15th century.
A full "coat of arms of God" in the Wernigerode Armorial , Southern Germany, c. 1490, with blue shield color, instead of the red used for the coat of arms of God in England.
Triangular form of the diagram with one vertex up, as found in an 1896 book
The modern coat of arms of the Anglican diocese of Trinidad .
Coat of arms of Trinity Parish, Jersey , Channel Islands .