From Gineipaedia, the Legend of Galactic Heroes wiki
Galactic civilizations have used a number of different year numbering systems by which to measure the passage of days, weeks and years. The primary four year numbering systems used in galactic history are the Common Era calendar, the Universal Calendar, the Imperial Calendar and the New Imperial Calendar. All four systems appear to use the same terminology as the Gregorian Calendar used on ancient Earth, differing only in that the starting dates are reset.
The Common Era calendar was adopted in the late 16th century CE on Earth. The first year of the calendar, 1 CE, was the estimated date of the birth of Jesus Christ, an important religious figure in ancient Earth history. The Common Era calendar fell into disuse some time after the advent of the Galactic Federation and the creation of the Universal Calendar in 2801 CE (1 UC).
The Universal Calendar was established in 2801 CE (1 UC) to commemorate the founding of the Galactic Federation. This calendar would come to be associated with the Golden Age of Humanity. The Universal Calendar was abolished in 310 UC (1 IC / 3110 CE) by Rudolf von Goldenbaum when he reorganised the Galactic Federation into the Galactic Empire.
The Universal Calendar would re-emerge in 527 UC (218 IC / 3327 CE) as a primary year numbering system, after more than two centuries of disuse, when Nguyen Kim Hua founded the Free Planets Alliance. The Universal Calendar would once again fall out of use once the Free Planets Alliance was defeated in the Second Alliance–Imperial War and absorbed into Emperor Reinhard von Lohengramm's New Galactic Empire.
The Imperial Calendar began in 310 UC (1 IC / 3110 CE) when Rudolf von Goldenbaum founded the Galactic Empire. It would be the galaxy's primary year numbering system until the fall of the Goldenbaum Dynasty in 799 UC (1 NIC / 490 IC / 3599 CE).
New Imperial Calendar
The New Imperial Calendar began in 799 UC (1 NIC / 490 IC / 3599 CE) when Reinhard von Lohengramm became the first emperor of the New Galactic Empire, uniting all of humanity for the third time in human history.
- The Gregorian Calendar was established by Pope Gregory XIII in 1582 CE. It was a modification of the Julian Calendar which had been in use since the days of the Roman Empire. Each year, defined by a single solar rotation, was divided into 12 months of roughly 30 days each. The twelve months are January, February, March, April, May, June, July, August, September, October, November and December, with January 1 being the first day of the new year. The Universal, Imperial and New Imperial Calendars all appear to use the same month names with the same number of days, and all appear to advance into the new year on the same date (January 1).
- The "Universal Calendar" is described with the abbreviation "U.C." in the animated OVA series. This presumably stands for "Universal Calendar."
- The "Imperial Calendar" is described with the abbreviation "R.C." in the animated OVA series. This presumably stands for "Reichs Calendar." We have changed the abbreviation to IC (Imperial Calendar) for the purpose of clarity. ("Reichs Calendar" is an amalgamation of English and German terminology).
- the "New Imperial Calendar" is described with the abbreviation "N.R.C." in the animated OVA series. This presumably stands for either "Neue Reichs Calendar" or "New Reichs Calendar." We have changed the abbreviation to NIC (New Imperial Calendar) for the purpose of clarity. ("Reichs Calendar" is an amalgamation of English and German terminology).