Ludolph van Ceulen (28 January 1540–31 December 1610) was a German mathematician who emigrated to the Netherlands. Born in Hildesheim, Germany, he moved to Delft to teach fencing and mathematics. In 1594 he opened a fencing school in Leiden. In 1600 he was appointed the first professor of mathematics at the University of Leiden. He died in Leiden.

Calculating π

Ludolph van Ceulen spent a major part of his life calculating the numerical value of the mathematical constant π, using essentially the same methods as those employed by Archimedes some 1800 years earlier. He published a 20-decimal value in his 1596 book Van de Cirkel ("On the Circle"), later expanding this to 35 decimals. After his death, the "Ludolphine number",

3.14159265358979323846264338327950288...,

was engraved on his tombstone in Leiden. The tombstone was later lost, but was restored in 2000.

External links

• Het grafschrift van Ludolph van Ceulen (in Dutch).