The mathematician who first calculated an accurate estimate of pi (π) was Archimedes of Syracuse, a Greek mathematician from around 287–212 BC. Archimedes used geometric methods involving polygons to approximate pi's value, estimating it to be between about 3.14084 and 3.14285, which is remarkably close to the true value of approximately 3.14159

. While Archimedes did not "discover" pi itself—since the concept of the ratio of a circle's circumference to its diameter was known earlier—he was the first to develop a rigorous method to calculate it with precision. His work laid the foundation for future mathematicians to refine the value of pi. The symbol π to represent this ratio was introduced much later, in 1706, by the Welsh mathematician William Jones, and popularized by Leonhard Euler in the 18th century