section_path: Origin/Early Roman numerals
section_name: Early Roman numerals
paragraph_text: Early Roman numerals
  
  The early Roman numerals for 1, 10, and 100 were the Etruscan ones: ⟨ 𐌠 ⟩, ⟨ 𐌢 ⟩, and ⟨ 𐌟 ⟩. The symbols for 5 and 50 changed from ⟨ 𐌡 ⟩ and ⟨ 𐌣 ⟩ to ⟨ V ⟩ and ⟨ ↆ ⟩ at some point. The latter had flattened to ⟨ ⊥ ⟩ (an inverted T) by the time of Augustus, and soon afterwards became identified with the graphically similar letter ⟨ L ⟩.
  
  The symbol for 100 was written variously as ⟨ 𐌟 ⟩ or ⟨ ↃIC ⟩, and was then abbreviated to ⟨ Ↄ ⟩ or ⟨ C ⟩, with ⟨ C ⟩ (which matched the Latin letter C) finally winning out. It might have helped that C was the initial letter of CENTUM, Latin for "hundred".
  
  The numbers 500 and 1000 were denoted by V or X overlaid with a box or circle. Thus, 500 was like a Ɔ superimposed on a ⋌ or ⊢, making it look like Þ. It became D or Ð by the time of Augustus, under the graphic influence of the letter D. It was later identified as the letter D; an alternative symbol for "thousand" was a CIↃ, and half of a thousand or "five hundred" is the right half of the symbol, IↃ, and this may have been converted into D.
  
  The notation for 1000 was a circled or boxed X: Ⓧ, ⊗, ⊕, and by Augustan times was partially identified with the Greek letter Φ phi. Over time, the symbol changed to Ψ and ↀ. The latter symbol further evolved into ∞, then ⋈, and eventually changed to M under the influence of the Latin word mille "thousand".
  
  According to Paul Kayser, the basic numerical symbols were I, X, 𐌟 and Φ (or ⊕) and the intermediate ones were derived by taking half of those (half an X is V, half a 𐌟 is ↆ and half a Φ/⊕ is D). Then 𐌟 and ↆ developed as mentioned above.