Background
Ceulen was born on January 28, 1540, in Hildesheim, Germany, the son of a merchant.
mathematician professor scientist
Ceulen was born on January 28, 1540, in Hildesheim, Germany, the son of a merchant.
Nothing is known of Ceulen's education.
After traveling widely, Ceulen settled in Holland, first, perhaps, in Breda and Amsterdam. In 1580 he was in Delft, where he became a fencing master and mathematics instructor. During 1589 he spent some time in Arnhem, and in 1594 Ceulen received permission to open a fencing school in Leiden.
In 1600 he was appointed teacher of arithmetic, surveying, and fortification at the engineering school founded in Leiden by Prince Maurice of Nassau. He held this position until his death. His second wife brought out Latin versions of two of his works posthumously, with the aid of Ceulen’s pupil Willebrord Snell. Ceulen was an indefatigable computer and concentrated on the computation of it, sometimes called Ludolph’s number. This brought him into controversy with the master reckoner Simon Van der Eycke, who had published an incorrect quadrature of the circle (1584-1586). Then he became acquainted with Archimedes’ The Measurement of the Circle, which his friend Jan Cornets de Groot, a mayor of Delft and father of Hugo Grotius, translated for him from the Greek. Now Ceulen began to work in the spirit of Archimedes, computing the sides of more regular polygons inscribed within and circumscribed about a circle than Archimedes had and inventing a special short division for such computation.
In his principal work, Van den Circkel (1596), he published TT to twenty decimal places by computing the sides of a regular polygon of 15 x 231 sides. He continued to work on this subject; and in his Arithmetische en geometrische fondamenten (1615), published by his widow, he reached thirty-three decimal places, always enclosing it between an upper and a lower limit. Finally, Willebrord Snell, in his Cyclometricus (1621), published Ceulen’s final triumph: it to thirty-five decimal places. This was inscribed on his tombstone in the Pieterskerk in Leiden. The Van den Circkel consists of four sections. The first and second sections are the most original; they contain not only the best approximation of it reached at that time but also show Van Ceulen to be as expert in trigonometry as his contemporary Viéte. In 1595 the two men competed in the solution of a forty-fifth degree equation proposed by Van Roomen in his Ideae mathematicae (1593) and recognized its relation to the expression of sin 45A in terms of sin A. Ceulen’s tables of interest were not the first to be published. He was anticipated by others, including his friend Simon Stevin (1583). Van Ceulen probably had computed his tables before he knew of Stevin’s work.
Ceulen married Adriana Symons in 1590. It is known that is was his second marriage.