Cistercian Monk Numerals

Cistercian numeration is a medieval system used by Cistercian monks between the 13th and 15th centuries. It allows any number from 0 to 9999 to be represented using a single symbol consisting of a vertical bar with a few added strokes around it. This system has recently been rediscovered and studied, notably by historian David A. King.

Cistercian numerals are constructed from a central vertical bar, around which lines are placed in four quadrants.

— ↗ Top right: units

— ↖ Top left: tens

— ↘ Bottom right: hundreds

— ↙ Bottom left: thousands

Each digit from 1 to 9 has a basic symbol (made up of small lines). The 0 has no symbol (the quadrant remains empty).

1		2		3
4		5		6
7		8		9

To compose a multi-digit number, place the symbol in the corresponding quadrant, adjusting it by rotation or symmetry.

The result is a single symbol combining these elements around the central vertical line.

To read a Cistercian number, observe the lines in each quadrant: and find the corresponding digit for the thousands (bottom left), hundreds (bottom right), tens (top left), units (top right) in order to reconstruct the decimal number.

Cistercian numeration was not intended for calculations or accounting. It was mainly used to identify and organize elements in manuscripts: page numbering, year markers, text divisions, lists or tables.

There is no evidence that Cistercian monks used decimal numbers. Their system was primarily used to record whole numbers, particularly for chronological references.

There is no evidence that they adapted this notation to fractions or decimal measurements.

A Cistercian number is easily recognized by its shape: a central line surrounded by small lines in the four corners.

All references to the Cistercian order and monks are clues.

This numbering system was brought to light by David A. King's book entitled The Ciphers of the Monks: a Forgotten Number-notation of the Middle Ages

The cistercian numeral system seems to have been created around the 14th century.