[d0mine]

There is no "0" year, 1 is the 1st year, so 100th year is still the 1st century, therefore 2nd century starts in 101 and 20th in 1901.

[notfed]

I find this decree frustrating. Someone could have just as easily said "the 'first' century starts at 1 BC" to account for this.

[Thorrez]

Then what is the last year of the first century BC? 2 BC? Now there's an off-by-2!

[karatinversion]

Do you also count the first decade of your life from January 1st of the year before you were born?

[Zambyte]

https://en.wikipedia.org/wiki/East_Asian_age_reckoning

[38]

Or better yet just year 0, why not? Do we say the 80s start in 1981?

[rdlw]

The concept of zero was not popularized in 500s Europe, when the system was devised.

[karatinversion]

And also, the system is a direct descendant of regnal numbering, where zero wouldn’t have made sense even if invented (there is no zeroth year of Joe Biden’s term of office).

[coldtea]

Doesn't matter, we can just agree the first century had 99 years, and be done with it.

We have special rules for leap years, that would just be a single leap-back century.

At the scale of centuries, starting 2nd century at 100 as opposed to 101 is just an 1% error, so we can live with it. For the kind of uses we use centuries for (not to do math, but to talk roughly about historical eras) it's inconsequential anyway.

[hypertele-Xii]

What? 0 is the year Jesus Christ was born.

[incognito124]

No, jesus was born in 1AD

[zimbu668]

"Most scholars, on this basis, assume a date of birth between 6 and 4 BC"

https://en.wikipedia.org/wiki/Chronology_of_Jesus