page_title: Roman numerals
section_title: Apostrophus
hierarchical_section_title: Roman numerals / Description / Large numbers / Apostrophus
caption_attribution_description: Deutsch: das Baujahre in römischer Zahlschrift an der Westerkerk-Kirche in Amsterdam
context_page_description: Roman numerals are a numeral system that originated in ancient Rome and remained the usual way of writing numbers throughout Europe well into the Late Middle Ages. Numbers in this system are represented by combinations of letters from the Latin alphabet. Modern usage employs seven symbols, each with a fixed integer value:
  The use of Roman numerals continued long after the decline of the Roman Empire. From the 14th century on, Roman numerals began to be replaced in most contexts by the more efficient Arabic numerals; however, this process was gradual, and the use of Roman numerals persists in some minor applications to this day.
  One place they are often seen is on clock faces. For instance, on the clock of Big Ben, the hours from 1 to 12 are written as:
  I, II, III, IV, V, VI, VII, VIII, IX, X, XI, XII
  The notations IV and IX can be read as "one less than five" and "one less than ten", although there is a tradition favouring representation of "4" as "IIII" on Roman numeral clocks.
  Other common uses include year numbers on monuments and buildings and copyright dates on the title screens of movies and television programs.
context_section_description: One of these was the apostrophus, in which 500 (usually written as "D") was written as IↃ, while 1,000, was written as CIↃ instead of "M". This is a system of encasing numbers to denote thousands (imagine the Cs and Ↄs as parentheses), which has its origins in Etruscan numeral usage. The IↃ and CIↃ used to represent 500 and 1,000 most likely preceded, and subsequently influenced, the adoption of "D" and "M" in conventional Roman numerals.
  In this system, an extra Ↄ denoted 500, and multiple extra Ↄs are used to denote 5,000, 50,000, etc. For example:
  Sometimes CIↃ was reduced to ↀ for 1,000. John Wallis is often credited for introducing the symbol for infinity (modern ∞), and one conjecture is that he based it on this usage, since 1,000 was hyperbolically used to represent very large numbers. Similarly, IↃↃ for 5,000 was reduced to ↁ; CCIↃↃ for 10,000 to ↂ; IↃↃↃ for 50,000 to ↇ; and CCCIↃↃↃ for 100,000 to ↈ.
caption: "1630" on the Westerkerk in Amsterdam. "M" and "D" are given archaic "apostrophus" form.
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