Jan de Witt

Jan de Witt attended Beeckman's school in Dordrecht, then in 1641 he entered the University of Leiden to study law. At university he showed remarkable talents, especially in mathematics and law. In 1645 Jan and his elder brother Cornelius visited France, Italy, Switzerland and England, then on his return Jan lived at The Hague as an advocate. He received a doctorate in law from University of Angers in 1645.

De Witt was an associate of van Schooten and lived for a while in his house. His most important work Elementa curvarum linearum (1659-61) was written before 1650, and was the first systematic development of the analytic geometry of the straight line and conic. It was published by van Schooten as part of his edition of Descartes' Géometrie (1660).

The word directrix is due to de Witt.

In 1650 de Witt was appointed the leader of Dordrecht's deputation in the government of Holland. Three years later he was appointed political leader of Holland.

As leader of Holland, de Witt applied his mathematical knowledge to the financial and budgetary problems of the republic. He wrote The Worth of Life Annuities Compared to Redemption Bonds which applied probability to questions of state finance.

De Witt brought about peace with England in 1654 and after this he was extremely successful in bringing prosperity to Holland. When war broke out again with England in 1665 de Witt was able to bring about a very satisfactory settlement at the Treaty of Breda (1667). His political skills were further seen in the Triple Alliance (1668) between the Dutch Republic, England and Sweden.

In 1672 France invaded and there were demonstrations against de Witt. His brother Cornelius was arrested on July 24 and two weeks later Jan de Witt resigned as political leader of Holland. When Jan came to visit Cornelius in prison they were attacked and killed by a large crowd. Quoting [2]:-

Cornelius was put to the torture and on August 19 sentenced to deprivation of his offices and banishment. His brother came to visit him in the Gevangenpoort at The Hague. A vast crowd, hearing this, collected outside and finally burst in, seized the two brothers, and tore them to pieces. Thus perished one of the greatest statesmen of his age and of Dutch history.

References (4 books/articles)

References elsewhere in this archive:

De Witt showed how a transformation of the axes could be used to reduce the equation for a conic to canonical form. Tell me more about this