Engraved bone found at Ishango (Democratic Republic of the Congo) and dated between 25,000 and 20,000 years B.P. The artefact is obtained from the leg bone of a baboon and is covered with a series of carvings ranged in three rows, occupying the full length of the object. The typology of the engravings seems to exclude a simply decorative purpose and rather suggests a system of recording or computing. According to Alexander Marshack’s interpretation, the engravings could represent the six months of a lunar calendar (Marshack 1972). These conclusions are not accepted unanimously by the scholars, nevertheless, if it is plausible to recognize a capacity to calculate and compute to earlier humankind, one cannot exclude that this ability could have been employed in the observation and reckoning of astronomical and seasonal cycles. The Ishango Bone is exhibited at the Royal Belgian Institute of Natural Sciences (Muséum des sciences naturelles), Brussels, Belgium (Heinzelin 1962).

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