Cistercian numbers are an ancient numeration system invented by the order of Cistercian monks in the 13th century. Its peculiarity is that it can represent very large numbers in a more compact format than both Roman and Arabic numerals.
With just one character, it is in fact possible to represent all numbers from 1 to 9,999. The system is in base 10 and uses signs and lines in a special way.
A vertical straight line acts as an axis dividing the plane into four quadrants, each one representing one of the four digits: the upper right quadrant for the units, the upper left quadrant for the tens, the lower right quadrant for the hundreds, and the lower left quadrant for the thousands.
It had its uses when it came to remembering dates and large numbers, but also had the major limitation of not allowing mathematical calculations. In a nutshell, It was a kind of monks’ exponential notation of the past.
It would be fascinating to find a way to also use it for calculations, that would become very compact even with huge numbers.