Two calendars, one night in Petrograd
The date discrepancy was not a time-zone issue or a later reinterpretation of events. In 1917, Russia still used the Julian calendar for civil dates, while most of Europe used the Gregorian calendar. The Bolsheviks’ seizure of key sites in Petrograd—the city now called St. Petersburg—took place on October 25 according to the Russian calendar, which was November 7 on the Gregorian one.
How the gap grew
The Julian calendar treats every fourth year as a leap year. The Gregorian calendar, introduced in 1582, keeps that rule for most years but skips leap days in century years unless the year is divisible by 400. That adjustment makes its average year more closely match the solar year. Because the calendars counted leap years differently, their dates drifted apart over centuries; by 1917, the Julian calendar was 13 days behind.
That meant the same moment had two legitimate civil dates, depending on which calendar a country used. Russia adopted the Gregorian calendar after the revolution, in 1918, so later accounts commonly give the event’s Gregorian date. The familiar name “October Revolution,” however, preserves the date used in Russia at the time.
Why the old name stuck
The revolution’s label is a small reminder that history is often recorded through the conventions people used then, not only those used now. “October” points to the calendar on which the Bolsheviks acted; “November” tells readers where that day falls on the calendar now standard in Russia and much of the world. Both dates describe the same seizure of power, not two separate events.
