# Roman Numerals on Buildings-why additive form rather than subtractive

**URL:** <https://boards.straightdope.com/t/roman-numerals-on-buildings-why-additive-form-rather-than-subtractive/1025133>\
**Category:** Factual Questions\
**Created:** [November 25, 2025, 10:44pm UTC](https://boards.straightdope.com/t/roman-numerals-on-buildings-why-additive-form-rather-than-subtractive/1025133 "2025-11-25T22:44:01Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![whc.03grady](https://avatars.discourse-cdn.com/v4/letter/w/a6a055/32.png) [@whc.03grady](https://boards.straightdope.com/u/whc.03grady)\
**Post date:** [November 25, 2025, 10:44pm UTC](https://boards.straightdope.com/t/roman-numerals-on-buildings-why-additive-form-rather-than-subtractive/1025133/1 "2025-11-25T22:44:01Z")

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I work at a public library, built as a Carnegie library, where the year of its construction,1903, is represented on its facade as ’MDCCCCIII’ rather than ‘MCMIII’. Cursory examination of other same-era buildings suggests this was common practice.

I have my own suspicions as to why, but wonder if there is a definitive/definitivish answer.

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**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\
**Post date:** [November 25, 2025, 11:01pm UTC](https://boards.straightdope.com/t/roman-numerals-on-buildings-why-additive-form-rather-than-subtractive/1025133/2 "2025-11-25T23:01:33Z")

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> [@whc.03grady](#):
>
> I have my own suspicions as to why, but wonder if there is a definitive/definitivish answer.

Romans seem not to have used the subtractive method much. Maybe IX, but IIII was more common than IV-IIRC (there was a Cecil article about clocks with Roman Numerals).

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**Author:** ![Elmer\_J.Fudd](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/elmer_j.fudd/32/1211_2.png) [@Elmer\_J.Fudd](https://boards.straightdope.com/u/Elmer_J.Fudd)\
**Post date:** [November 26, 2025, 1:41am UTC](https://boards.straightdope.com/t/roman-numerals-on-buildings-why-additive-form-rather-than-subtractive/1025133/3 "2025-11-26T01:41:58Z")

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I suspect the subtractive form was originally considered a form of abbreviation and inappropriate for non-ephemeral substrates like buildings and monuments. Using the subtractive would be akin to engraving “The Carnegie Libr.”