olemus
aastanumber islami ajaarvamise süsteemis,
alguspunkt on 622 CE
=
the year number in islamic lunar calendar

ülevaateid
https://en.wikipedia.org/wiki/Hijri_year

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

https://aau.ac.ae/en/blog/how-and-why-did-the-hijiri-calendar-begin