# Thaïs Bone

The Thaïs Bone is an engraved - or notched - bovine rib fragment, discovered in the Thaïs cave (Grotte de Thaïs, variants Thaï/Taïs/Taï) in Saint-Nazaire-en-Royans, Département de la Drôme, France.
The object dates from the end of the last Ice Age - around 12,000 years ago - having been created by people of the early Azilian culture, of the early Mesolithic period (sometimes referred to as Azilian-Epipalaeolithic).
It has been on display at the Musée de Valence since 2006.

## Significance

The composition of markings on the Thaïs bone represent the most elaborate time-factored sequence currently known within mobile Palaeolithic art.
In 1991, the American archaeologist Alexander Marshack demonstrated that the notches were not a decorative representation, but a system for recording time. He conducted meticulous analysis of the bone fragment during the 1970s and 80s, and a comparative study of one hundred European notched bones. He proposed that the engraved notches corresponded to the notation of lunisolar astronomical observations, and constituted one of humanity's first calendars.

## Discovery and studies

The bone was discovered during excavations carried out in the Thaïs cave, between 1968-69, by two locals from Drôme: Jacques Léopold Brochier, an archaeologist, and his cousin Jacques-Elie Brochier (it was then called the Taï cave). Prior to this a limited exploration of the cave was undertaken in 1878, facilitating access to the water-filled galleries. The Brochiers conducted initial studies on the bone fragment during the early 1970s; analysis continued in stages over the next twenty years, with the substantive analysis and interpretation carried out by Alexander Marshack.
The notched bone artefact was found among the remains of marmots and ibex. It forms part of a large archaeological set of engraved bones and pebbles deposited at the end of the Last Glacial Period (LGP) - during a period of prehistoric fauna and megafauna migration.

## Description and interpretation

The Thaïs Bone fragment measures 87mm × 27 mm, and is engraved on both faces.
The composition consists of a boustrophedon sequence of short horizontal containing lines or sections, each of which carries irregular subsets of marks; none of the carvings could have occurred naturally.
The engravings are non-decorative, and represent a complex, cumulative, non-arithmetical notational system of time-reckoning, and recording, based upon daily lunisolar observations - over the course of as much as 3.5 years.
The shape of the overall pattern suggests that the sequence was kept in step with the seasons by observations of the solstices.
The process of aligning the lunar phase (month) with the seasons of the solar - or tropical - year within lunisolar calendars is called intercalation.
According to the calendrical analysis the accumulation of notations on the bone therefore represent a form of visual cueing and problem-solving.
The complex nature of the markings, coupled with their proposed calendrical purpose carries profound implications for the understanding of European early Mesolithic (Azilian-Epipalaeolithic) culture, and within the fields of archaeoastronomy, and the history of art, calendars, and chronometry.