The Roman numeral for 1000 is "M".Roman numerals are a numeral system that originated in ancient Rome and were used throughout the Roman Empire. The Roman numeral system was developed in ancient Rome during the 3rd century BC.The system uses letters from the Latin alphabet to represent numbers. The Roman numeral system has been in use for over two thousand years and has had a lasting impact on Western culture.

The Roman numeral system, a numerical notation that employs letters from the Latin alphabet to signify values, holds a profound legacy in the history of mathematics, commerce, and cultural heritage, tracing its origins back to ancient Rome.

The Roman numeral system evolved gradually over centuries, originating in the early stages of the Roman Republic around the 3rd century BC. Initially, Romans used a primitive system known as the "additive system," where they represented numbers by adding up various symbols. As the Roman Empire expanded and developed, the numeral system underwent refinement and sophistication.

The core symbols of the Roman numeral system include:

- I for 1
- V for 5
- X for 10
- L for 50
- C for 100
- D for 500
- M for 1000

The system's structure relies on combinations and placement of these symbols to represent different values. For instance, placing smaller numerals before larger ones (e.g., IV for 4, IX for 9) represents subtraction, while their addition depicts larger values (e.g., VI for 6, XI for 11).

Roman numerals found extensive usage across the Roman Empire, notably in commerce, accounting, architecture, monumental inscriptions, and in the dating of important events and milestones. They were employed on coins, legal documents, architectural structures (like the Pantheon in Rome), and sundials, among other artifacts, showcasing their widespread application in daily life.

Despite the eventual adoption of more efficient positional numeral systems (like Arabic numerals) in contemporary mathematics and global commerce, Roman numerals continue to maintain a symbolic presence in Western culture. They persist in various contexts, such as clock faces, book chapters, movie credits, and even for distinguishing monarchs' names (e.g., Henry VIII).

Their enduring legacy resonates in their cultural significance, symbolizing tradition, antiquity, and a link to classical civilizations. Roman numerals serve as a timeless reminder of the enduring legacy and influence of ancient Roman culture on modern society, retaining their relevance as a symbolic representation of history and heritage.