The Gregorian calendar is the calendar used in most parts of the world. [1][a] It went into effect in October 1582 following the papal bull Inter gravissimas issued by Pope Gregory XIII, which …

Dec 15, 2025 · The Gregorian calendar is the solar dating system now in general use. It was proclaimed in 1582 by Pope Gregory XIII as a reform of the Julian calendar. The Gregorian calendar differs from …

May 22, 2025 · The Gregorian calendar has become the standard for measuring the progression of time since Pope Gregory XIII first introduced it in the year 1582. His papal influence let it spread to Italy, …

Sep 13, 2012 · The original goal of the Gregorian calendar was to change the date of Easter. In 1582, when Pope Gregory XIII introduced his Gregorian calendar, Europe adhered to the Julian calendar, …

Since the discrepancy between the Julian calendar year and the astronomical seasons kept growing over time in the centuries that followed, more days had to be skipped in countries that switched to …

A detailed history of the modern Gregorian calendar. Learn about its Roman origins, the reforms of Julius Caesar, and Pope Gregory XIII's crucial introduction of the leap year rule.

Among the myriad calendar systems that have been developed over millennia, the Gregorian calendar stands out as the most widely used today. Named after Pope Gregory XIII, this calendar system was …

Apr 28, 2025 · How the modern calendar we use today was developed and why it replaced the Julian calendar. Learn about Pope Gregory XIII's reforms and the calendar's global adoption.

Sep 14, 2024 · The Gregorian calendar was introduced in 1582 by Pope Gregory XIII to reform the previous Julian calendar, which had become misaligned with the seasons. Here is a detailed history …

Jan 1, 2025 · Introduction The Gregorian calendar, introduced by Pope Gregory XIII in 1582, remains the globally accepted standard for measuring time. But did you know its primary purpose was to …