Detail from Cotton Faustina manuscript B. VII, folio 42v, showing a "Scutum Fidei" or Shield of the Trinity triangular diagram, with a representation of Christ on the cross.

This is part of a ca. 1210 illustration to the Compendium Historiae in Genealogia Christi by Peter of Poitiers (or Petrus Pictaviensis).

The Latin text on the shield in the image includes the words or scribal abbreviations for "PATER" (the Father), "SPIRITUS SANCTUS" (the Holy Spirit), and "FILIUS" (the Son) in the three outer nodes, and "DEUS" (God) in the center node. The text in the links connecting the outer nodes to each other reads "NON EST" (Is not), while the text along the links connecting the center node to the outer nodes reads "EST" (Is).

For the history and meaning of this general "Shield of the Trinity" or "Scutum Fidei" diagram of traditional western Christian symbolism (a visual summary of the first part of the Athanasian Creed), see the main article en:Shield of the Trinity. The reason for placing "Filius" in the bottom node of this version of the diagram, with a illuminated representation of the Crucifixion above it, is presumably the same as for a ca. 1250 version of the diagram included in Matthew Paris' Chronica Majora, where the diagram was annotated with the Latin Vulgate version of the Biblical passage meaning "The Word was made flesh" (from the Gospel of John, verse 1:14).

This is the chronologically earliest known version of the Scutum Fidei or