Annus Novus Decimal Calendar

Conscious of the potentially negative impact of cultural chauvinism on its activities the Empire of Atlantium has a history of striving to develop systems and symbolism that reflect its innovative, inclusive, secular, global, cross-cultural and trans-national nature.

As early as 10505 (1986) the Imperial Senate considered the introduction of alternatives to the inefficient, sectarian Gregorian calendar and dating system which remains in use throughout much of the first world.

A system known as the Imperial Universal Standard (IUS) Calendar - with a 400-day year, divided into 10 months of 40 days - was eventually introduced on 3 Decimus, 10506 (13 November, 1987). Unfortunately the unfamiliar non-terrestrial nature of the IUS Calendar proved to be a significant impediment to its general acceptance, and the system fell into disuse around 10509 (1990).

In a move that provided a catalyst for the re-examination of the calendar issue within Atlantium, the IUS system was formally abandoned by directive of Emperor George II shortly after the Refundatio in 10518 (1999). The rejected 10505-10506 (1986-87) calendar proposals were then revisited, and one of them, the proposed Imperial Decimal Standard (IDS) Calendar was selected as the basis of a viable new Atlantian calendar and dating system.

A modified and renamed variant of the IDS Calendar was introduced as the Annus Novus Decimal Calendar System (AND) - the official calendar of record for the Empire of Atlantium - on 1 Primus, 10520 (1 January, 2001).

The Annus Novus year is of the standard terrestrial duration. The Annus Novus Calendar divides the year into 10 months alternating between 36 and 37 days in length, and 73 weeks of 5 days. In leap years - which are concurrent with those of the Gregorian system, to aid simplicity - an intercalary 1-day month called the Intercalarius is inserted between the last day of the old year and the start of the new year. 

The Annus Novus Leap Year Rule is as follows:

An Annus Novus year has an Intercalarius if and only if either
(i) year+281 is divisible by 4 but not by 100 or
(ii) year+281 is divisible by 400

The months of the Annus Novus year are named after Latin ordinal numbers:

Primus (36 days)
Secundus (37 days)
Tertius (36 days)
Quartus (37 days)
Quintus (36 days)
Sextus (37 days)
Septimus (36 days)
Octavus (37 days)
Nonus (36 days)
Decimus (37 days)

The days of the Annus Novus week are likewise based on modified Latin ordinals - for example Primidi = primus (first) + dies (day):

Primidi
Secundi
Tertidi
Quartidi
Quintidi

The Annus Novus year-numbering convention is derived from the approximate date for the worldwide end of the Pleistocene Era and the last Ice Age, and the beginning of the Holocene. Annus Novus years are counted from 10,501 before Atlantium's foundation in 10500 (1981), and the first year of the numbering convention is Year 0. The Gregorian year 2000 for example is known as 10519 NE (or "of the New Era"). Years prior to Year 0 are identified as OE ("Old Era").

All official communications and documentation in Atlantium utilise the Annus Novus system, although to avoid undue confusion the traditional Gregorian equivalents are also usually provided.

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For further information about the Empire of Atlantium or the Annus Novus Decimal Calendar, contact us by email.