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[[Date Conversion]]: Each [[Major Race]] uses their own dating system, rendering ''date conversion'' between systems necessary on occasion. The following article outlines the workings of each system and defines the reference date that determines year 0 in each and how to convert dates between various systems. 
* Please see [[Dating System]]s for more information.
* Please see [[History]] for a list of events.

== Description ([[Specifications]]) ==
''Equivalent Dates of Charted Space:'' Here is a set of dates comparatively dated to several calendars in common usage throughout [[Charted Space]]:
{| class="wikitable sortable"
|- 
! Solomani
! Imperial
! Vilani
! Zhodani
! Aslan
! K'Kree
! Event
|-
| 3621 BC
| [[-8145]] 
| 3,148 PI
| -639.1
| -5,442
| 1
| Start of [[K'Kree]] calendar
|-
| 2208 BC
| [[-6731]]
| 2,046 PI
| 1.1
| -5,301
| 1,186
| Start of [[Zhodani]] calendar
|-
| AD 1
| [[-4520]]
| 361 PI
| 981.2
| -2,779
| 3027
| [[Solomani]] calendar begins
|-
| AD 475
| [[-4045]]
| 1 VI
| 1,192.2
| -2,237
| 3,422
| Start of [[Vilani]] calendar
|-
| AD 2436
| [[-2083]]
| 1,496 VI
| 2,058.3
| 0
| 5,055
| [[Aslan]] calendar Begins
|-
| AD 4518
| [[0]]
| 3,084
| 2,979.3
| 2,376
| 6,788
| Start of {{imperial}} calendar
|}

=== Conversion Chart ===
Read down for date of origin, then across to calendar to convert.
{| class="wikitable sortable"
|- 
!colspan="8"| Date Conversion
|-
! Source (x)
! to Solomani
! to Imperial
! to Vilani
! to Zhodani
! to Aslan
! to K'Kree
! to Hiver
|-
!from Solomani
|n/a
|(x - 4521) / 1.0006644
|
|
|
|
|
|-
!from Imperial
|(x * 1.0006644) + 4521
|n/a
|(x + 4045)/1.312
|(x + 6731)/2.26
|(x + 2083) / 0.877
|(x + 8145) / 1.2
|(x - 410)*2
|-
!from Vilani
|
|(x * 1.312) - 4045
|n/a
|
|
|
|
|-
!from Zhodani
|
|(x * 2.26) - 6731
|
|n/a
|
|
|
|-
!from Aslan
|
|(x * 0.877) -2083
|
|
|n/a
|
|
|-
!from K'Kree
|
|(x * 1.2) - 8145
|
|
|
|n/a
|
|-
!from Hiver
|
|(x/2) + 410
|
|
|
|
|n/a
|}
''NOTES:'' Note that converting from a calendar that does not have a zero year (e.g. Solomani, Vilani, Zhodani, K'kree)  i.e. the 0 point is an instant in time, rather than a complete year, must account for the "missing" year when going from "negative" dates to positive ones.

== History & Background ([[Dossier]]) ==
'''Primary Calendars of the Imperium:''' As the largest and most dominant polity, the calendars of the Imperium have been central to interstellar trade and history although despite their wide use, they are still not an ''official'' or ''standardized'' galactic calendar. 

=== Imperial Calendar ===
:''Main article: [[Imperial Calendar]]''

The [[Third Imperium]] uses a regularized version of the calendar originally developed on [[Terra (world)|Terra]]. It shares seconds, minutes, hours, days and weeks with the [[Solomani]] version, but does not organize them into intermediate months. The Imperial year is exactly 365 days, or 52 weeks with one extra "[[Holiday]]" date. The calendar is, naturally, tied to the declaration of the founding of the Imperium by [[Cleon I]].

=== Solomani Calendar ===
:''Main article: [[Revised Gregorian Calendar]]''

The [[Solomani]] have kept the same dating system that was in use before the Solomani invention of [[jump drive]] and coming into contact with the [[Ziru Sirka]]. Its reference date is tied to the birth of a popular religious figure from early Terran history.

The Imperial Calendar is heavily influenced by the Solomani dating system, and borrows most of its basic timekeeping units. However, instead of numbering days within a year, as in Imperial practice, days are numbered inside a ''month'', twelve roughly equal subdivisions of the year. Further, the ''length'' of the year is subtly different as Solomani calendar still periodically adjusts to synchronize with the sidereal period of Terra around Sol (365.2425 days, thus the Solomani year is 1.0006644 Imperial years). Because of this difference, the first day of the two calendars are 0.74 years apart as of [[1116]].

=== Vilani Calendar ===
The [[Vilani]] also count from the founding of the Empire [[Ziru Sirka]]. Each Vilani year is ~1.312 [[Solomani]] year.

=== Other Major Race  Calendars of Charted Space ===
Many other races employ calendars and time-keeping systems of importance to trade and history.

==== Aslan Calendar ====
:''Main article: [[Aslan Calendar]]''

[[Aslan]] dating begins from the formation of the [[Tlaukhu]]. Each Aslan year is ~0.877 [[Solomani]] years.

==== Droyne Calendar ====
The [[Droyne]] calendar likely should start around -75,000 {{Imperial}}, however the Droyne don't keep good records.

==== Hiver Calendar ====
:''Main article: [[Hiver Calendar]]''
[[Hive Federation]] dates begin with the official proclaiming of [[Glea (world)|Glea]] as the Federation capital. This occurred in [[410]] imperial, though the move was not officially completed until [[490]]. While all official dates refer to this calendar, most Hiver nests use local dating systems. 

A Cycle (day) is a little over 22 hours. A year is 143 cycles, each cycle simply numbered 1 to 143 with no month or week divisions. Thus, a Hiver year is about half an Imperial one (0.49 specifically).

1105 is 1389 HF; 1111 is 1401 HF{{page cite|name=Hivers|version=Classic Traveller|page=2}}

==== K'Kree Calendar ====
:''Main article: [[K'kree Calendar]]''
The [[K'Kree]] dating system is also pre-flight. Each K'Kree year is ~1.2 [[Solomani]], Their calendar starts with the founding of [[Rak'keer!]], their capital city in -8145 Imperial.

==== Vargr Calendar ====
Vargr do not have a calendar used throughout the [[Vargr Extents]]. The a Vargr "year" is ~1.03 [[Solomani]] years, based upon the Vargr homeworld of [[Lair (world)|Lair]], but even this is not consistently used throughout the Extents. 

==== Zhodani Calendar ====
:''Main article: [[Zhodani Calendar]]''
The [[Zhodani]] ''chten'' is ~0.754 standard years. The calendar uses Olympiads, which is three ''chten'', with an extra day to cover the leap years. An Olympiad is ~2.262 standard years. The Zhodani calendar uses the count of olympiad from the founding of the [[Psionic Games]], plus a marker of which year (1, 2, or 3) into the current olympiad (e.g. 1244.1).

== References & Contributors ([[Sources]]) ==
{{Intermediate}}
{{Sources
|S1= {{Ludography cite|name= Library Data (A-M) |page=10}}
|S2= {{Ludography cite|name= The Traveller Book |page=152-153}}
|S3= {{Ludography cite|name= Aslan |version=Classic Traveller|page=36}}
|S4= {{Ludography cite|name= Zhodani |version=Classic Traveller|page=8}}
|S5= {{Ludography cite|name= Solomani |version=Classic Traveller|page=12}}
|S6= {{Ludography cite|name= Imperial Encyclopedia |page=6-7}}
|S7= {{Ludography cite|name= Referee's Companion |page=42-45}}
|S8= {{Ludography cite|name= Milieu 0 |page=89-91}}
|S9= {{Ludography cite|name= GURPS Traveller Core Rules |page=15-19}}
|S10= {{Ludography cite|name= Alien Races 2 |page=19}}
|S12= Contributor: Lord (Marquis) and Master of Sophontology [[Maksim-Smelchak]] of the [[Ministry of Science]] 
}}

{{LE|Chronology|Dating systems|Imperial}}