The Coligny calendar is a bronze plaque with an inscribed calendar, made in Roman Gaul in the 2nd century CE. It lays out a 5-year cycle of a lunisolar calendar, each year with 12 lunar months. An intercalary month is inserted before each 2.5 years. It is the most important piece of evidence enabling the reconstruction of an ancient Celtic calendar.

The calendar was found in 1897 in France, in Coligny, Ain (near Lyon), along with broken pieces of a life-size bronze statue of a nude male holding a spear, likely meant to portray Mars, the Roman god of war. Approximately 40% of the original calendar remains in the form of fragments. It was engraved on a bronze tablet, preserved in 73 fragments, that was originally 134.8 cm wide by 78.0 cm high. With the rim attached the plate measured 52 by 32 (2.75 cm to the ). It is written in the Gaulish language with the Latin alphabet, using Roman square capitals and Roman numerals. Based on the style of lettering and the accompanying statue, the bronze plaque likely dates to the end of the second century CE, although copying errors indicate that the calendar itself is much older. It is now held at the Gallo-Roman Museum of Lyon-Fourvière.thumb|140px|right|Bronze statue found with the calendar, possibly [[Mars (mythology)|Mars, reconstituted by A. André.]]

Eight small fragments of a similar calendar were found at the double-shrine of Villards-d'Héria. It does not have the holes of a peg calendar though it potentially conflicts with the month of which refers to Gaulish "winter".

and divide the calendar into summer and winter seasons of six months, each season led off by a festival of several days marked with IVOS. This indicates an early version of the same traditional seasons as seen in later Celtic contexts: "For two divisions were formerly on the year, viz., summer from Beltaine (the first of May), and winter from Samuin to Beltaine".

Allowing for variations between lunar and solar years and aligning the month names to the solar year's seasons, Samonios may have begun on the first quarter moon around May–June; if aligned to the modern Gaelic festivals Beltane, Lughnasadh, Samhain and Imbolc, Samonios might have begun around on the first quarter moon around April—May.

{| class="wikitable"

|-

!! rowspan="2"| Order || rowspan="2"| Name || rowspan="2"| Days || rowspan="2"| Etymology || colspan="3"| Interpretation

|-

! Samoni !! Solar !! Gaelic<br/>Festivals

|-

! I-1

| ? || 29/30? || Unknown meaning || Sep-Oct || Apr-May || Mar-Apr

|-

! 1

| || 30 || Gaulish "summer". between them. The first half has 15 days (cóicthiges 'fifteen-days' in Old Irish, coicís 'fortnight' in Irish)., the second has either 14 or 15 days, with DIVERTOMV in place of the 15th day on a 14 day half as a 'virtual' day for notations.

Pliny the Elder reported that the Celtic month began on the 'sixth day of the new moon'. includes the latest information about the intercalary notations and the triple marks. Olmsted (2001) and anfad and Old Irish mad and ni-mad..

The summer season has 4 MAT and 2 ANMAT months, the winter season has 2 and 4 respectively. MAT months have 30 days and ANMAT months have 29 days with the exception of Equos that can have 30 days in years 1 and 5.

{| class="wikitable floatright"

|+ Order of MAT and ANM months

|-

! rowspan="2"| Type

|-

! 1 || 2 || 3 || 4 || 5 || 6

|- style="background: yellow"

! style="background: yellow" | MAT

| SAM || RIV || OGR || CVT || SIM || AED

|-

! ANM

| GIA || EQV || ELE || CAN || DVM || ANA

|}

The order of the MAT and ANMAT months is determined by the seasons; MAT months start in Summer on Samonios and ANMAT months start in Winter on Giamonios. This order is used for determining the triple mark and PRINI LOVD/LAG notations across the days of the month.

MAT month days are initially assigned M D (or MD) "good/auspicious day", and ANMAT month days are initially assigned D "neutral day". The terms M D and D refer to daylight hours in apposition to N "night". Any notation with N overwrites the full daytime notation, including triple marks, M D, D and D AMB.

The notation D AMBRIX RI

thumb|upright=2.0|the D AMB pattern (orange) for a lunar month

D AMBRIX RI, usually shortened to D AMB, denotes an inauspicious day. It occurs only on Days 5 and 11 in the upper half-month, that being the period when the moon is more than half full, so it's mostly left free of inauspicious days. In the second half-month, D AMB is placed on every odd numbered day except Day 1, but this is explained by the traditional view that the unit 1 is neither odd nor even. <!-- end of "refs=" -->

Bibliography

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  • The Gallic calendar – Lugdunum Museum