Roman numerals came from an ancient system of numeracy and their values are:-
M=1000, D=500, C=100, L=50, X=10, V=5 and I=1
The numbers that we use today of: 0 1 2 3 4 5 ... etc originated from the ancient Hindu-Arabic numeral system.
Ancient Rome.
In ancient Rome, 754BCE.
The Roman numeral system is based on the Etruscan numeral system and the Etruscans once had a powerful influence over the ancient Romans.
Today the equivalent of 399 as a Roman numeral is CCCXCIX but the ancient Romans would have notated the numeral quite differently.
Nowadays 1842 as a Roman numeral is MDCCCXLII but the ancient Romans would have notated it as MDCCCXXXXII
As a Roman numeral in today's terms it represents 1444 but the ancient Romans probably wrote it out quite differently.
The equivalent of 579 as a Roman numeral is now DLXXIX but the ancient Romans would have chosen DLXXVIIII
Under today's rules now governing the Roman numeral system the Roman numeral for 54 is LIV but the ancient Romans would have notated it as LIIII
Under today's rules now governing the Roman numeral system 946 as a Roman numeral is CMXLVI but the ancient Romans would have notated it quite differently
No, the number 0 does not have a corresponding Roman numeral. Roman numerals were developed by the ancient Romans and do not include a representation for the concept of zero.
Under the rules now governing the Roman numeral system 1949 is deemed to be MCMXLIX as a Roman numeral but the ancient Romans would have notated it as MDCCCCXXXXVIIII
Nowadays the equivalent of 1973 as a Roman numeral is MCMLXXIII but the ancient Romans would have notated the numeral quite differently.