## 11 January 2021

### 13th century numeral system

A single icon can represent any number up to 9999 (see bottom row).  It's not hard to decipher.  Break the icon into four quadrants, then read the bottom left, then bottom right, then top left, then top right.

I have no further information on the system, or its name.  The via at Reddit indicates that it was developed by Cistercian monks and was "used for years, divisions of texts, the numbering of notes and other lists, indexes and concordances, arguments in Easter tables, and even for musical notation."

This system is explained - somewhat slowly - in a Numberphile video (hat tip to reader Keith).

1. There was a recent numberphile video that covered this, fascinating. https://www.youtube.com/watch?v=9p55Qgt7Ciw

1. Thank you, Keith. I've added the link to the body of the post.

2. Could you imagine working out a quadratic equation with that? I'd lose my mind. But I suppose the people who used that would not appreciate our system.

3. I am the one who shared it on Reddit (the OP, not the reposter that you linked), Imgur and Twitter. This has a Wikipedia article called Cistercian numerals. There is a book too called The Ciphers of the Monks (2001) by David A. King that talks about it. This one is the most complete source of information about the subject.

1. Did they fact to use them to protect themselves?

2. It's just that arabian numerals weren't popular yet. Cistercian numerals were more efficient than roman numerals, althought they didn't use it for arithmetic, fractions or accounting. Its use declined over the centuries, although it briefly resurfaced during the 15th century.

4. They remind me of Futhark runes, is there any connection?