Cistercian Numbers represent a medieval numeral system developed by Cistercian monks in the early 13th century as a compact way to write numbers. Using these numerals, any number from 1 to 9,999 can be written in a single glyph by combining basic elements along a vertical line. The system was apparently based on a numeral system introduced by John of Basingstoke, Archdeacon of Leicester.

These numerals served as an efficient alternative to Roman numerals, allowing complex numbers to be represented with a single symbol rather than multiple characters. The system saw use for several centuries, continuing in some applications until the early 20th century. Modern resources include downloadable Excel charts and video explanations that demonstrate how the glyph combinations work.

The system's elegance lies in its geometric approach to number representation, where position and orientation along the vertical line determine the value. While largely replaced by Arabic numerals in most contexts, Cistercian Numbers remain of interest to historians, mathematicians, and enthusiasts of alternative numeral systems. Resources for learning about the system include Wikipedia, dCode, and various educational websites that preserve this medieval mathematical innovation.