# Ludolph van Ceulen

Ludolph van Ceulen | |
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Born | Hildesheim, Bishopric of Hildesheim, Holy Roman Empire |
28 January 1540

Died | 31 December 1610 Leiden, Dutch Republic |
(aged 70)

Fields | Mathematics |

Institutions | Leiden University |

Notable students | Willebrord Snellius Frans van Schooten, Sr. |

Known for | Ludolphine number |

**Ludolph van Ceulen** (German: [fan ˈkɔʏlən], Dutch: [vɑŋˈkøːlə(n)]; 28 January 1540 – 31 December 1610) was a German-Dutch mathematician from Hildesheim. He emigrated to the Netherlands.

Van Ceulen 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 Leiden University. 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 seventeen hundred years earlier. He published a 20-decimal value in his 1596 book *Van den Circkel* ("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 eventually lost, but later restored in 2000.

## External links

- Ludolph van Ceulen at the Mathematics Genealogy Project
- "Digits of Pi" by Barry Cipra (includes photo of tombstone)
- Oomes, R. M. Th. E.; Tersteeg, J. J. T. M.; Top, J. "The epitaph of Ludolph van Ceulen."
*Nieuw Arch. Wiskd. (5)***1**(2000), no. 2. online (Dutch) - MacTutor biography of van Ceulen
- "Ludolph van Ceulen (1540-1610)" (in Dutch). Archived from the original on 5 May 2006. Retrieved 31 March 2008. <templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
- Ludolph van Ceulen (1596)
*Vanden circkel*- Linda Hall Library - Ludolph van Ceulen (1619)
*De circulo et adscriptis liber*and*Surdorum quadraticorum arithmetica*- Linda Hall Library