Roman numerals were used by the ancient Romans for the first time in their CNC system. Roman numerals originated about 500 years from Etrusca BC. The Roman numeral system is decimal, but there is no direct position, excluding zero. This system is based on the alphabet of letters to show the sum of their values (or, in some cases, differences), which is combined.

Roman numeral is a counting system used in ancient Rome. It was widely used before the introduction of Arabic numerals. At present, you may still see it in clocks, calendars, article sorting, buildings, periodic tables of elements, etc., because its use is gradually decreasing.

Source: @creas99