A Flemish mathematician from Bruges (Netherlands), I actually was employed as a quartermaster and commissioner of public works.
My pamphlet De Thiende (i.e. The Tenth) was responsible for introducing the use of decimal fractions to the Western world as a common computational technique.
I was neither the inventor nor the first sysetematic user of decimals, being predated many centuries earlier by mathematicians in China and Persia.
The notation I used for decimals (called the Bombelli-inspired notation) is now considered to be clumsy and unnecessarily related to sexagesimal fraction notation.
Predating Galileo in a scientific discovery, I simultaneously dropped two lead spheres of different weights and discovered that they landed at the same instant.
Simon Stevin (1548-1620)