Assertion: gregorian calendar | /r/HasProperty | introduced
Facets:
Source sentences:
text: It only includes countries that officially used the Julian calendar before the Gregorian calendar was introduced; countries that switched from a different calendar system to the Gregorian calendar, such as Saudi Arabia in 2016, are excluded.
text: Many European countries did not adopt the Gregorian calendar when it was introduced, mainly because of the Protestant Reformation that was taking place at that time.