The solar calendar in use throughout most of the world, sponsored by Pope Gregory XIII in 1582 as a corrected version of the Julian calendar. See table at calendar.

格列高利历，公历：世界绝大部分通用的阳历，由教皇格列高利十三世于1582年倡导使用，为朱利安历法的改进版。

youdao

In 1582, in Italy and Spain, this day became the first day of the Gregorian Calendar after it was adopted by Pope Gregory XIII.

CNN: Tuesday,

The so-called Meridian Hall, created to verify the accuracy of the calendar Pope Gregory XIII promulgated in 1582, is in the Vatican Secret Archives, which hold some 10m documents stored by the papacy over the past 1, 200 years.

ECONOMIST: The Vatican turns a page��slowly

Ask Julius Cesar and Gregory XIII!

UNESCO: International Women��s Day: why the 8 of March?