http://letmegooglethat.com/?q=XX+century http://letmegooglethat.com/?q=XX+century https://en.wikipedia.org/wiki/Roman_numerals#Modern_use_in_continental_Europe

http://letmegooglethat.com/?q=XX+century http://letmegooglethat.com/?q=XX+century https://en.wikipedia.org/wiki/Roman_numerals#Modern_use_in_continental_Europe https://en.wikipedia.org/wiki/Roman_numerals#Modern_use_in_c... It is the standard way of writing the century in many European countries/languages.