Who Invented Gregorian Calendar. It was introduced by pope gregory xiii as a way of correcting the julian calendar and its yearly measurements. The reform, which established what became known as the gregorian calendar and laid down rules for calculating the date of easter, was well received by such astronomers as.

The gregorian calendar is the dominant calendar used in most countries around the world today. The gregorian calendar was introduced in 1582 by pope gregory xiii to reform the previous julian calendar, which had become misaligned with the seasons.