Re: The Emacs Calculator and calendar

[Christoph Herzog]

On 10/09/2012 12:39 AM, Richard Stallman wrote:
> Did the Ottoman empire use the Islamic calendar?

They used two calenders at the same time. One Hijri (lunar Islamic 
calendar) and one Mali (fiscal, Julian calendar based but Hijri-years). 
There were so-called Sıvış years (leap years) that were omitted in the 
fiscal calendar (roughly every 30 years), until at some point they 
decided to let the years diverge so that by the beginning of the 20th 
century there was a difference of two years, e.g. 1324 Mali was 1908 as 
was 1326 Hijri.

Basically, the important (and hard) thing is to have reliable calendar 
conversion. It makes sense to use the Gregorian calendar as a reference 
system, as a kind of yardstick (or tertium comparationis, if you like) 
to easier compare and relate dates given in different historical 
calendar systems even if, strictly speaking, it may be anachronistic.