Behold the Ishango bone! It may seem small (10 cm or almost 4 inches), but not only is it ancient — to the tune of 20,000 years old — but it also might be the first known recorded lunar calendar, perhaps indicating that a woman developed some of the earliest mathematics.
But let’s back up a bit. The Ishango bone was discovered in 1950 in what is now than Democratic Republic of Congo by a Belgian anthropologist named Jean de Heinzelin de Braucourt, and it’s probably the fibula of a mammal. You can see that there are a series of noches carved onto the bone. The noches are unlikely to be random and are grouped into three columns with tallies of 48, 60, and 60.
Scientists and mathematicians have debated what the noches were meant to tally — prime numbers? An arithmetic game? Some sort of slide-rule? A major theory advanced by Alexander Marshack is that the Ishango bone shows a six-month lunar calendar. Building from that idea is the argument by Claudia Zaslavsky that a woman was the most likely creator of this artifact, since using a lunar calendar would have been common for women to do as a way to keep track of their menstrual cycles.
Sources: “Mathematical Treasure: Ishango Bone” Frank J. Swetz, Mathematic Association of America, Convergence (March 2014). Claudia Zaslavsky, “Women as the first mathematicians,” Women in Mathematics Education Newsletter, vol 7, number 1, Jan 1992.
