Julian calendar
Pre-Gregorian date system
The Julian calendar is the system of timekeeping introduced by Julius Caesar in 46 BCE, which established the 365-day year with a leap year every four years.
It served as the standard calendar in the Western world until the Gregorian calendar replaced it in 1582.
The Julian calendar drifts about one day every 128 years relative to the solar year, which prompted the reform.
Some Orthodox churches still use the Julian calendar for religious observances.
Insertion between existing elements
- leap yearCalendar with added day
- quadrennialEvery four years
- solar cycleRecurring pattern of stellar activity
- annual cycleRecurring twelve-month pattern
Ancient state from Augustus onward
- ancient RomeEarly Italian empire city
- chronologyTemporal ordering of events
- datingPursuing romantic connections
- Anno DominiYears since Christ's birth
B.C. · A.D. · era · epoch · antiquity · medieval · historiography · historical documents
Sun crosses celestial midline
- solsticeDay of maximum tilt
- solar yearOne complete Earth orbit
- precessionRotating axis gradually reorients
- vernal equinoxSpring's astronomical beginning
Rome's chief religious official
- solar yearOne complete Earth orbit
- standardizationImplementing uniform technical specifications
- decreeAuthoritative legal command
- adoptionLegal family formation
intercalation
Insertion between existing elements
- leap yearCalendar with added day
- quadrennialEvery four years
- solar cycleRecurring pattern of stellar activity
Roman Empire
Ancient state from Augustus onward
- ancient RomeEarly Italian empire city
- chronologyTemporal ordering of events
- datingPursuing romantic connections
Anno Domini · B.C. · A.D. · era · epoch · antiquity · medieval · historiography · historical documents · ancient world
equinox
Sun crosses celestial midline
- solsticeDay of maximum tilt
- solar yearOne complete Earth orbit
- precessionRotating axis gradually reorients
pontifex maximus
Rome's chief religious official
- solar yearOne complete Earth orbit
- standardizationImplementing uniform technical specifications
- decreeAuthoritative legal command
superseded
Replaced by something newer
- correctionFixing of mistakes
- ten daysSlightly more than a week
- timekeepingclock, watch, watches, clocks, timer
- Caesar's legacyRoman Empire, Augustus, dictatorship, Senate, assassination
- calendarsalmanac, almanacs, planners, diaries, datebooks
- calendar quirksleap day, leap year, intercalation, Metonic cycle, precession
- Roman CalendarSeptember, October, November, December, nones
- astronomystars, moon, sun, planet, planets
Julian calendarlunar calendar
Timekeeping by moon phases
Islamic calendar · Hebrew calendar · Chinese calendar · Hindu calendar · lunisolar calendar