Ludolph van Ceulen

Ludolph van Ceulen (1540 to 1610) was a German-Dutch mathematician from Hildesheim who spent much of his life calculating the constant pi by the polygon method of Archimedes. He published a value to 20 decimal places in his 1596 book Van den Circkel and later extended it to 35 decimals, so that pi was long called the Ludolphine number in Germany. He taught fencing and mathematics in Delft and Leiden, and in 1600 became the first professor of mathematics at the Engineering School of Leiden University. His record for hand calculation of pi shows how far patient arithmetic could go before machines took over the work.