Ishango bone

The Ishango bone is a bone tool, dated to the Upper Paleolithic era, about 18000 to 20000 BC. It is a dark brown length of bone, the fibula of a baboon, with a sharp piece of quartz affixed to one end, perhaps for engraving or writing. It was first thought to be a tally stick, as it has a series of tally marks carved in three columns running the length of the tool, but some scientists have suggested that the groupings of notches indicate a mathematical understanding that goes beyond counting.

The Ishango bone was found in 1960 by Belgian Jean de Heinzelin de Braucourt while exploring what was then the Belgian Congo. It was discovered in the African area of Ishango, which was centered near the headwaters of the Nile River at Lake Edward (now on the border between modern-day Uganda and Congo). The lakeside Ishango population of 20000 years ago may have been one of the first counting societies, but it lasted only a few hundred years before being buried by a volcanic eruption.

The artifact was first estimated to originate between 9000 BC and 6500 BC. However, the dating of the site where it was discovered was re-evaluated, and is now believed to be more than 20,000 years old.

The Ishango bone is on permanent exhibition at the Royal Belgian Institute of Natural Sciences, Brussels, Belgium.