Why is 21st century called 21st century?

[anonymus]

The time period 1900-1999 was called 20[SUP]th[/SUP] century even though all years in in began with 19XX.

Should it not have been called 19[SUP]th[/SUP] century instead of 20[SUP]th[/SUP].

What are the historical reasons to do so?



@Joe Shearer @Dillinger @Ayush @Oscar @Bang Galore @hinduguy @notsuperstitious @samantk

 

[livingdead]

The time period 1900-1999 was called 20[SUP]th[/SUP] century even though all years in in began with 19XX.

Should it not have been called 19[SUP]th[/SUP] century instead of 20[SUP]th[/SUP].

What are the historical reasons to do so?



@Joe Shearer @Dillinger @Ayush @Oscar

0 - 100 is first century.... not zeroth century.

 

[Haseebullah]

I did not see that coming.

 

[Ayush]

already answered

 

[notsuperstitious]

Same reason why this is your seventh year running and not sixth

Joking.

20 centuries completed, hence 21st running.

 

[Joe Shearer]

Just out of curiousity, how would you, @anonymus, count the century from 0 to 100?

Enquiring minds want to know.