Indictions to Years (indiction to yr)
1 indiction equals 15 years exactly.
How to convert indictions to years
To convert indictions to years, multiply the number of indictions by 15. This factor is exact. To go the other way, multiply years by 0.06666666667 (rounded).
years = indictions × 15
Example: 10 indictions = 150 years.
Months and years are not constant. This site uses the average Gregorian year of 365.2425 days, so one 'year' converts to 365.2425 days, not 365; use 'common year' for exactly 365 days.
About these units
Indiction (indiction)
A 15-year tax cycle introduced under the Roman Empire and used to date documents in the Byzantine and medieval worlds.
Indictions began as periodic reassessments of land or poll taxes in the Roman Empire, and the Latin indictio means an imposition or levy. Evidence exists for a 15-year cycle across the empire, a 14-year cycle in Roman Egypt, and a five-year cycle. Tax changes and arrears remissions tended to fall at the start of a cycle, with examples recorded under Nero in 58 AD and Hadrian in 118 AD.
Constantine is credited with turning the 15-year cycle into a dating system in 312 AD, and Egypt used it by 314 AD, though sources disagree on the first year, with one Coptic document implying 297 to 298. Justinian required indictions in dated documents in 537 AD. The year began on 23 September in the early Eastern Empire, later moving to 1 September, while Bede gives 24 September for the West and papal practice started on 25 December or 1 January. Because the length is a convention of 15 years, the figure used here is 15 Gregorian years, about 473.4 million seconds. The cycle also forms part of the 7,980-year Julian Period.
1 indiction = 473,354,280 seconds (exactly).
Sources: Wikipedia: Indiction
Year (yr)
The average Gregorian calendar year of 365.2425 days (31,556,952 seconds). A common year has 365 days and a leap year 366.
A year is the Earth's trip around the Sun, but there are several versions. The tropical year, which tracks the seasons, is about 365.2422 days. The sidereal year, measured against the stars, is about 365.2564 days, roughly 20 minutes longer, because the Earth's axis precesses. Calendars must squeeze these into whole days, which is the origin of leap years. English year descends from Old English gear, while Latin annus, the source of annual, comes from a different root.
The Gregorian calendar, introduced by Pope Gregory XIII's bull of 24 February 1582, fixed the problem of Julian drift that had moved the March equinox away from 21 March and upset the date of Easter. Ten days were skipped, so Thursday 4 October was followed by Friday 15 October. Its rule of skipping leap days in century years not divisible by 400 gives a mean year of 365.2425 days, the value this site uses for the year. Britain and its empire switched in 1752 and Russia in 1918. Scientists write the year as a, with the Julian year fixed at 31,557,600 seconds.
1 year = 31,556,952 seconds (exactly).
Sources: Wikipedia: Year; Wikipedia: Gregorian calendar
Related conversions
- Years to indictions (reverse)
- Indictions to seconds
- Indictions to minutes
- Indictions to hours
- Indictions to days
- Indictions to weeks
- Indictions to months
- Seconds to years
- Minutes to years
- Hours to years
- Days to years
- Weeks to years
- Months to years
- Milliseconds to years
- Microseconds to years
- Nanoseconds to years
- Decades to years
- Centuries to years
- Millennia to years
See all time units.