The Antikythera Mechanism is a unique Greek geared device, constructed around the end of the second century bc. It is known1, 2, 3, 4, 5, 6, 7, 8, 9 that it calculated and displayed celestial information, particularly cycles such as the phases of the moon and a luni-solar calendar. Calendars were important to ancient societies10 for timing agricultural activity and fixing religious festivals. Eclipses and planetary motions were often interpreted as omens, while the calm regularity of the astronomical cycles must have been philosophically attractive in an uncertain and violent world. Named after its place of discovery in 1901 in a Roman shipwreck, the Antikythera Mechanism is technically more complex than any known device for at least a millennium afterwards. Its specific functions have remained controversial11, 12, 13, 14 because its gears and the inscriptions upon its faces are only fragmentary. Here we report surface imaging and high-resolution X-ray tomography of the surviving fragments, enabling us to reconstruct the gear function and double the number of deciphered inscriptions. The mechanism predicted lunar and solar eclipses on the basis of Babylonian arithmetic-progression cycles. The inscriptions support suggestions of mechanical display of planetary positions9, 14, 15, now lost. In the second century bc, Hipparchos developed a theory to explain the irregularities of the Moon’s motion across the sky caused by its elliptic orbit. We find a mechanical realization of this theory in the gearing of the mechanism, revealing an unexpected degree of technical sophistication for the period.

The Gaulish Coligny calendar was found in Coligny, Ain, France (46°23′N 5°21′E) near Lyon in 1897, along with the head of a bronze statue of a youthful male figure. It is a lunisolar calendar. It is now held at the Gallo-Roman Museum of Lyon.

It was engraved on a bronze tablet, preserved in 73 fragments, that originally was 1.48 m wide and 0.9 m high (Lambert p. 111) or approximately 5 feet (1.5 m) wide by 3½ feet in height.[1] Based on the style of lettering and the accompanying objects, it probably dates to the end of the 2nd century AD.[2][3] It is written in Latin inscriptional capitals and is in the Gaulish language (Duval & Pinault). The restored tablet contains sixteen vertical columns, with 62 months distributed over five years.

The French archaeologist, J. Monard, speculated that it was recorded by druids wishing to preserve their tradition of timekeeping in a time when the Julian calendar was being imposed throughout the Roman Empire. However, the general form of the calendar suggests the public peg calendars (or parapegmata) found throughout the Greek and Roman world (Lehoux pp. 63–65).

A similar calendar found nearby at Villards d'Heria (46°25′N 5°44′E) is only preserved in eight small fragments. It is now preserved in the Musée d'Archéologie du Jura at Lons-le-Saunier.

The Celts, according to Rome, were a warring and illiterate people. Yet Terry Jones discovers that these people had mathematical know-how beyond Rome's. It was a society built on an advanced and complex trading network that spread way beyond the borders of the Celtic world. So why was Caesar so hell-bent on the destruction of these civilised people?