1582 was a common year starting on Monday in the Julian calendar , and a common year starting on Friday in the Proleptic Gregorian calendar . It saw the beginning of the Gregorian calendar switch, the assassination of Oda Nobunaga in Japan, and the Raid of Ruthven in Scotland. Discover why 10 days disappeared in October 1582 with our detailed overview of the Gregorian calendar reform. Learn about its impact on society, its historical context, and the global adoption of the new calendar system. Imagine waking up in 1582 and finding that ten days had just disappeared from your calendar . The Gregorian calendar reform of 1582 eliminated ten days from After years of consultation and research, Pope Gregory XIII signed a papal bull in February 1582 promulgating the reformed calendar that came to be known as the Gregorian calendar.
