Medieval-style version of the "Shield of the Trinity" diagram of traditional western Christian symbolism, shown on a red shield.  The three nodes at the edge of the diagram are labelled with the Latin-language names of the three persons of the Trinity: The Father ("PATER"), The Son ("FILIUS"), and The Holy Spirit (scribal abbreviation of "SPIRITUS SANCTUS"). The node in the center of the diagram (within the triangle formed by the other three nodes) is labelled God (Latin "DEUS"), while the three links connecting the center node with the outer nodes are labelled "is" (Latin "EST"), and the three links connecting the outer nodes to each other are labelled "is not" (Latin "NON EST") -- showing that the three persons of the Trinity are all God, but are not the same as each other.  All connecting links between nodes are non-directional (two-way).
This was considered to be the heraldic coat of arms of God (or of the Trinity) in 15th-century England and France.  The "banner of the Trinity" which Jean Le Fevre, Seigneur of St. Remy, and Jehan de Wavrin attest that Henry V of England displayed at Agincourt would have been the same (but with the emblem on a red flag instead of a red shield).  See File:Scutum Fidei on Holy Trinity pulpit - geograph.org.uk - 1061634.jpg for a photograph of a church decoration.  A Victorian medievalesque version of this can be seen at http://www.heraldsnet.org/saitou/parker/Jpglosst.htm#Trinity as part of the on-line version of the 1894 book "A Glossary of Terms Used in Heraldry" by James Parker.
For one medieval version of this coat of arms of God (though with a blue background, instead of the red used in England), see File:Wernigeroder Wappenbuch 010.jpg .

For further explanation, a heraldic blazon, and links to other medieval versions of this diagram, see the main Shield of the Trinity article.  For alternative versions of this diagram on Wikimedia Commons, see Image:3enighed.svg , Image:Shield-Trinity-Scutum-Fidei-basic.png , Image:Trinidad-Anglican-Episcopal-Coat-of-Arms.svg , Image:Trinity-Parish-Jersey-Coat-of-Arms.svg , Image:Trinity knight shield.jpg (medieval), and Image:PetrusPictaviensis_CottonFaustinaBVII-folio42v_ScutumFidei_early13thc.jpg (medieval).
Own work -- This is an SVG version of Image:Shield-Trinity-medievalesque.png .
This graphic was converted from the following PostScript code (note that this program references the "Zapf Chancery Medium Italic" font, which is part of the Basic 35 Postscript fonts, but not the Basic 14):

%!
/L{rlineto}def/m{moveto}def/x{0 0}def/c{newpath
60 0 360 arc gsave 1 1 1 setrgbcolor fill
grestore stroke}def/v{rmoveto}def/M{x]makefont
setfont}def/r{rotate}def 2.75 setlinewidth/t{
/ZapfChancery-MediumItalic findfont}def gsave
1.035 dup scale 563.2318840 413.309179 m 0
285.724637 L -529 0 L 0 -285.724637 L
0 -5 0 -5 1 -17 rcurveto
16 -192 162 -248 262 -248 rcurveto
4 0 L 100 0 245 56 261 248 rcurveto
1 12 1 12 1 17 rcurveto gsave 1 x setrgbcolor
fill grestore stroke grestore 9.1875 28
translate/X{t[60 0 -6 60 M}def/Z{X 49.5 0 v
(non e)show .7 0 v(st)show}def/W{X 14 -1.75 v
(e)show .7 0 v(st)show}def 95.587 575.075 m
180.598 -144.434 L 0 -228.241 L 47.63 0 L 0
228.241 L 180.587 144.434 L -23.815 41.25 L
-180.587 -144.434 L -181.137 144.434 L gsave 1
1 1 setrgbcolor fill grestore stroke gsave 0 1
translate 514 641 m -429 0 L -25 -18 L
2 -77 15 -165 55 -244 rcurveto
39 -77 98 -159 160 -202 rcurveto
49 0 L 62 42 121 125 160 202 rcurveto
40 79 54 166 56 243 rcurveto
491 594 m -3 -53 -15 -125 -49 -194 rcurveto
-37 -74 -92 -153 -142 -185 rcurveto
-50 32 -106 111 -143 185 rcurveto
-34 69 -45 141 -48 194 rcurveto closepath
gsave 1 1 1 setrgbcolor fill grestore stroke 1
x setrgbcolor 57 628 m 0 -8 L 8 0 L 0 8 L fill
x 0 setrgbcolor 174 603.75 m Z gsave 62 r 420
-237 m Z grestore gsave -62 r -387 292 m Z
grestore grestore 300 444.391 c 110.85 590.7 c
489.15 590.7 c 300 227.4 c gsave 38.64 r 583
145.5 m W grestore gsave -38.64 r -206 520.3 m
W grestore gsave -90 r -381 288 m W grestore t[
54 0 -5.4 54 M 60 584 m(p)show -.5 0 v(ater)
show 442 584 m(\256lius)show 259 241.5 m(spt)
show .6 0 v(s)show 280.5 242 m(\305)show 265
187 m(sct)show .6 0 v(s)show 282 187.5 m(\305)
show 246 431.75 m t[61.5 0 -6.15 61.5 M 1.5 0
(deu)ashow 1.5 0 v(s)show showpage
%EOF
AnonMoos