In Roman numerals, there is no specific symbol for zero. Instead, the Latin word "nulla," which means zero, was used to represent the concept of zero. The Roman numeral system was not based on place value, and the Romans did not have a need for a numeral to represent zero in their trading and bartering activities. The concept of zero was introduced by Indian mathematicians in a place value system, and it spread with trade along the Silk Road to China and the Islamic world. Therefore, the absence of zero in Roman numerals is attributed to the historical development of the numeral system and the specific needs of the Roman civilization.