The decimal point is 150 years older than we thought
nature.com
nature.com
"The earliest known appearance of the decimal point was in the interpolation column of a sine table in Christopher Clavius's Astrolabium (1593) [...] We trace Clavius's use of decimal fractional numeration and the decimal point back to the work of Giovanni Bianchini (1440s), whose decimal system was a distinguishing feature of his calculations in spherical astronomy and metrology."