MUL.APIN

The first tablet is a map made of lists. It opens with the stars of the three paths, the northern path of Enlil, the equatorial band of Anu and the southern path of Ea, some sixty six stars and constellations assigned each to its road across the sky, with the Plough, the Old Man, the True Shepherd of Anu, the Bull of Heaven and the rest of the Babylonian sky-figures in their places, many of them ancestors of the constellations still in use.

There follow the dates, month by month in the ideal calendar, on which stars first rise from the sun's glare, the pairs that rise as others set, the intervals in days between risings, and the stars the moon touches in its monthly course, the ziqpu stars that culminate overhead completing the toolkit. The second tablet turns to the wanderers and the calendar: the paths of the sun and the five planets through the same star-roads, the lengths of planetary visibility and invisibility, the solstices and equinoxes fixed in the ideal year, shadow-length tables for the hours of the day, water-clock weights for the watches of the night, and the rules for declaring an intercalary month when star-risings show the lunar year drifting against the seasons. Appended omens tie the whole to the diviner's craft. The scheme idealises, its year an even 360 days for calculation, and that very idealisation shows the compilers reaching past observation toward model-making.

The oldest dated manuscript of MUL.APIN was written in 687 BCE, but the work it copies is older: the observations underlying its rising dates point, by modern analysis, to the late second millennium, around 1300 to 1000 BCE, at a latitude consistent with Assyria or Babylonia, and the compendium as a fixed two-tablet series likely reached its standard form around the turn of the millennium. From then it was scribal canon.

Copies survive from Nineveh's royal libraries, from Assur, Babylon, Uruk and other cities across seven centuries, remarkably stable in text, and excerpts and school extracts show it in the curriculum wherever the scribal art was taught. Its practical work was calendrical and divinatory at once: the same lists that told a temple when to intercalate a month told the observers of the omen series Enuma Anu Enlil what the sky ought to do, so that deviation could be read as a signal. In the longer history of science its position is pivotal.

MUL.APIN gathers the pre-mathematical astronomy of Mesopotamia, the stage of named stars, ideal periods and arithmetical schemes, out of which the Late Babylonian astronomers of the last centuries BCE built genuinely predictive mathematical astronomy, and through them Greek astronomy inherited the zodiac's raw material, several constellation figures, and the sexagesimal degree it still uses. The standard modern edition and study, by Hunger and Pingree and their successors, keeps the old reference work in scholarly service.