Important Events in the History of π


And he made a molten sea, ten cubits from one brim to the other; it was round all about, and his height was five cubits: and a line of thirty cubits did compass it round about.
1 Kings 7:23


The following list is not meant to be all-inclusive of all information about π, especially the chronology for every record of digits calculated.

 ca 1650 BCEgyptian scribe Ahmes wrote the Rhind Papyrus documenting that the Egyptions used the equivalent of (16/9)2 ≈ 3.16049.
3rd cent BCArchimedes of Syracus (287-212 BC) developed the polygonal scheme and established 3 10/71 < π < 3 1/7 (≈3.14084 < π < ≈3.14286) and used 211875/67441 ≈ 3.14163 49
2nd cent ADClaudius Ptolemy (87-165 AD) published the value 3+8/60+30/3600 ≈ 3.14167
5th cent ADZu Chongzhi (430-501) established 3.14159 26 < π < 3.14159 27 using the polygonal method.
1424π computed to 14 digits by Al-Kashi from Samarkind.
1573Valentius Otto used 355/113 (≈3.14159 29203 5).
1671James Gregory discovers the arctan series.
1610π computed to 35 digits by Ludolph van Ceulen using a polygonal approximation.
1706First use of the symbol π to represent the ratio of the circumference to the diameter of a circle by William Jones in Synopsis Palmariorum Matheseos.
Not adopted for general use until 1737 when used by Leonard Euler in Variae observationes circa series infinitas.
1706π computed to 100 digits by John Machin using an arctan series.
1761π proved to be irrational by the Swiss mathematician Johann Heinrich Lambert.
1874π computed to 527 digits by William Shanks (actually computed 707 digits, but error was found in the 528th place in 1946).
1882π proved to be transcendental by the mathematician Carl Louis Ferninand von Lindemann.
1947π computed to 808 places by D. F. Ferguson using a desk calculator.
1949first time 1,000 digits of π computed—2037 digits using the computer ENIAC (previous record was 808 digits)
1958π computed to 10,021 digits using a Pegasus computer by Felton at the Paris Data Processing Center.
1961π computed to 100,265 digits using an IBM 7090 computer at the IBM Data Processing Center in New York by Daniel Shanks and John M. Wrench, Jr.
1973π computed to 1,000,000 digits using an CDC 7600 computer by Jean Guilloud and Martine Bouyer.
1976Richard Brent and Eugene Salamin published a new iterative and quadratic algorithm to determine π.
1989David and Gregory Chudnovsky published a new very fast series to compute π.
1989π computed to 1,011,000,000 digits by David and Gregory Chudnovsky on a home build computer, m zero.
 1995David Bailey, Peter Borwein, and Simon Plouffe publishes an efficient method to compute the nth hexadecimal digit of π without having the previous n-1 digits.
2002π computed to 1,241,100,000,000 digits using an Hitachi SR8000/MP supercomputer by Yasumada Kanaka and coworkers at the University of Tokyo.