How and by whom roman numerals started?

Answer 1

It is not known exactly when the Roman numerals started. They were not started by by anyone in particular. They were the result of several centuries o evolution.

It is thought that the Roman numeral system was derived from a tally system where tally marks were carved on wooden tally sticks which was in use in archaic Italy. This system was in use by shepherds in Italy until the 19th century. Thus, it originated from the notches of the tally mark system, which gave 1 as I, 2 as II and 3 as III. Every fifth notch there was the symbol Ʌ for 5, which was a double cut. The tenth notch was cross cut, giving a X. The system was originally complicated and was later simplified. The number 8 which had been IIIIVIII was abbreviated to ɅIII, where Ʌ represented four previous notches. A further abbreviation was to turn four, which had been four tally marks (IIII), into IɅ. Over the centuries with the development of the Latin alphabet the tally marks eventually became identified with the Latin letters I, V and X. Thus the symbol Ʌ was inverted to become V.50 was written in a number of ways N, И, K, Ψ, ⋔ or ᗐ. It had acquired a standard symbol, ⊥ , by the time of Augustus and later it was inverted as it became identified with the letter L. 100 was Ж, ⋉, ⋈, H. The symbols for 50 plus an extra stroke Ж (X superimposed on I) became the main one and was written as >I< or ƆIC. It was later abbreviated as Ɔ or C. C finally became the standard symbol because it was the initial letter of the word centum (hundred). 500 was a Ɔ superimposed on a ⋌or ⊢ -. It became D or Ð by the time of Augustus and finally settled as the letter D. 1000 was an encircled X, Ⓧ. By the time of Augustus the Greek letter phi (Φ) was in use. It changed again to Ψ and ↀ, then to ∞ and then to⋈. Finally it became M, the first letter of the word mille (thousand).