[beginner] What's wrong?

[Chris Angelico]

On Sat, Apr 2, 2016 at 3:27 PM, Random832 <random832 at fastmail.com> wrote:
> On Fri, Apr 1, 2016, at 19:29, Michael Selik wrote:
>> Humans have always had trouble with this, in many contexts. I remember
>> being annoyed at folks saying the year 2000 was the first year of the new
>> millennium, rather than 2001. They'd forgotten the Gregorian calendar
>> starts from AD 1.
>
> Naturally, this means the first millennium was only 999 years long, and
> all subsequent millennia were 1000 years long. (Whereas "millennium" is
> defined as the set of all years of a given era for a given integer k
> where y // 1000 == k. How else would you define it?)
>
> And if you want to get technical, the gregorian calendar starts from
> some year no earlier than 1582, depending on the country. The year
> numbering system has little to do with the calendar type - your
> assertion in fact regards the BC/AD year numbering system, which was
> invented by Bede.
>
> The astronomical year-numbering system, which does contain a year zero
> (and uses negative numbers rather than a reverse-numbered "BC" era), and
> is incidentally used by ISO 8601, was invented by Jacques Cassini in the
> 17th century.
>

Are you sure? Because I'm pretty sure these folks were already talking about BC.

http://xenohistorian.faithweb.com/holybook/quotes/YK.html

ChrisA