Petra-Sancta system

heraldry

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

July 23, 2026

Quick Summary

The Petra-Sancta system is a method devised by Sylvester Petra-Sancta to represent heraldic colors in black-and-white illustrations. This system uses specific line patterns to denote different tinctures: argent (plain field), gules (perpendicular lines), azure (horizontal lines), vert (lines from dexter chief to sinister base), purpure (lines from sinister chief to dexter base), and sable (crossed lines). Furs like vair and countervair are shown with spots or alternating lines and plain surfaces. This system aids in the accurate blazoning, or describing, of heraldic arms, which is the process of identifying the field and any charges (symbols) on a shield.1

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

2 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

heraldry
The reading of heraldry
…as the system of Sylvester Petra-Sancta, an Italian herald, it makes use of the following equivalents: argent is denoted by a plain field, or by dots or points, gules by perpendicular lines, azure by horizontal lines, vert by lines from dexter chief to sinister base, purpure by lines from sinister…
Read More
…as the system of Sylvester Petra-Sancta, an Italian herald, it makes use of the following equivalents: argent is denoted by a plain field, or by dots or points, gules by perpendicular lines, azure by horizontal lines, vert by lines from dexter chief to sinister base, purpure by lines from sinister…
Read More