Gregorian Calendar Adopted: 10 Days Vanish in 1582
Pope Gregory XIII deleted ten days from the calendar in October 1582 to correct a drift that had accumulated since Julius Caesar's reform in 46 BC. Thursday, October 4 was followed immediately by Friday, October 15. Catholic countries like Spain, Portugal, and Italy complied at once. Protestant nations refused on principle, preferring astronomical error to papal obedience. Britain waited until 1752, by which point the gap had grown to 11 days. Russia held out until 1918. Greece didn't switch until 1923. The Julian calendar drifted one day every 128 years. The Gregorian calendar drifts one day every 3,236 years, meaning it won't need correction until roughly the year 4818. The reform also moved New Year's Day from March 25 to January 1 in most adopting countries.
October 4, 1582
444 years ago
Key Figures & Places
What Else Happened on October 4
Rebels breached the walls of Chang'an, ending the short-lived Xin dynasty and the reign of Emperor Wang Mang. This violent collapse plunged China into years of …
Wang Mang's head ended up in the imperial treasury. Rebels stormed Chang'an during a peasant uprising, captured the emperor, killed him, and cut off his head. T…
Heraclius sailed from Carthage to Constantinople with a fleet and an army. Emperor Phocas had murdered his way to power eight years earlier and driven the empir…
Pope Innocent III crowned Otto IV as Holy Roman Emperor in Rome, formalizing a fragile alliance between the papacy and the Welf dynasty. This coronation briefly…
Caliph al-Adil II ruled the Abbasid Caliphate for six months. His vizier had him assassinated and replaced him with his uncle. Al-Adil was 25. The Abbasid Calip…
The Byzantine-Venetian War ended in 1302 after eight years of fighting over trade routes and Mediterranean ports. Venice kept its commercial privileges in Const…
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