What was the first theoretical calculation of a value of pi was that of?

The first theoretical calculation of a value of pi is attributed to the ancient mathematician Archimedes of Syracuse, around 250 BCE. He approximated pi by inscribing and circumscribing polygons around a circle, calculating the perimeters of these polygons to estimate the value of pi between 3.14 and 3.142857. Archimedes' method laid the groundwork for future calculations and understanding of this important mathematical constant.