Where did Roman numerals come from? Despite their name, Roman numerals evolved from an Etruscan system of counting, which may possibly have come from Ancient Greece. The Romans popularized the system and left it for us to see, which is why we gave it their name.
Here is a refresher course in Roman numerals. I means 1, V means 5, X means 10, L means 50, C means 100, D means 500, and M means 1,000. If you put one numeral before a larger one, it means minus. So, IV is five minus one, which is four. If you put a smaller numeral after a larger one, it means plus. So, VI is five plus one, which is six. You always add or subtract the smaller number from the larger number. So, CM is 1,000 minus one hundred, which is 900. And MC is 1,000 plus 100, which is 1,100. This year, 2026, would be written as MMXXVI (2 thousands, 2 tens, a 5 and a 1).
Roman numerals are a good way of writing numbers and they are very easy to carve because they mostly have only straight lines. However, they do have several problems that were addressed with Arabic numerals. The first problem is that with this system you cannot write any number higher than 3,999, because there is no letter for 5,000 or 10,000. If the numerals are only used for dates and simple calculations, that is no real problem, but if anyone needs to do complex mathematics, it does become a hindrance. There were a few solutions to this. One was to put a bar over the top of the Roman numerals, which multiplied the number by 1,000. So XL is 40, but XL with a line over it would be 40,000. Another way was to use the “apostrophus” system, which uses a C and a reversed Ɔ to build bigger values, where each new set multiplies the number by a factor of 10. IƆ is 500. CIƆ is 1,000, CCIƆƆ is 10,000, CCCIƆƆƆ is 100,000 and so on. A little confusing.
The second problem is that there is no zero in Roman numerals. Of course they had the concept of zero, as in nothing, but they didn’t have a zero as a numerical place holder the way Arabic numerals do. That means that Roman numerals become longer as numbers become more complex. 3,888 is MMMDCCCLXXXVIII. It also makes mathematics difficult because it is difficult to do addition, subtraction, multiplication, and division. They usually got around this by using an abacus for the calculation part and then Roman numerals to write down the result. As the Indians realized when they came up with the system of numbers that travelled into the Middle East and then into Europe as Arabic numerals, having a zero and having a positional system of writing numbers makes mathematics a lot easier.
As with a lot of their culture, the Romans picked up the numerals they used from Etruria, which was a civilization that occupied a large part of northern Italy. Etruria was swallowed up by Rome in the end, but there are theories that the first kings of Rome were actually Etruscan. They borrowed and then adapted Etruscan numbers from roughly the 8th century BC, right at the beginning of Rome’s history. They carried on using them for thousands of years and, as we still use them occasionally today, they have far outlasted the Roman Empire. Nobody knows where the Etruscan number system came from, but there is a theory that it may have come from Greek Attic numerals, which are remarkably similar. However, as there is not much time between the development of the Attic system and the Etruscan system, they may have both evolved from a different common ancestor.
The fact that they evolved simultaneously is likely because as a way of writing numbers, Roman numerals, and other straight line systems like them, are numbers you can write using sticks or with simple marks on wood, stone or clay. Most early alphabets make use of straight lines because they are easier to carve and easier to read. Many cultures used tally sticks to count things like cattle, and you can only lay down so many sticks before it becomes necessary to use a different character. The human eye can quickly recognize three sticks, but four or more and we need to stop and count them. Having different symbols from four onwards made sense. Chinese numbers follow the same pattern. 1 to 3 are lines, then 4 is a character. 一二三四. Roman numerals are probably a logical evolution from counting with sticks. They were not designed for fast written calculation, but they did their job extremely well for labeling, recording, and carving. And this is what I learned today.
Sources
https://en.wikipedia.org/wiki/Etruria
https://historylearning.com/a-history-of-ancient-rome/history-of-roman-numerals
https://en.wikipedia.org/wiki/Roman_numerals
https://en.wikipedia.org/wiki/Etruscan_numerals
https://en.wikipedia.org/wiki/Attic_numerals
https://www.geeksforgeeks.org/maths/why-roman-numerals-dont-have-the-number-zero
Photo by The Daphne Lens: https://www.pexels.com/photo/large-blue-clock-with-roman-numerals-on-stone-wall-37323132/