Dutch jurist and professor in Leiden, remembered for the most influential Dutch speech of the 20th century.
His father was the lawyer Jacobus Pieters Cleveringa (17 july 1863, Appingedam – 17 January 1932, Amsterdam). His mother, Lutgerdina Catharina Lucretia Schleurholts ( 18 August 1867, Bedum – 2 April 1942, Haarlem), was the daughter of the physician and mayor of Bedem, Hieronymus Ulferts Schleurholts (7 February 1834, Bedum – 10 June 1913, Bedum). He had a younger sister Afina Cecilia (17 March 1898, Appingedam – 17 August 1925, Heemstede), who died at young age.
He spent most of his youth in Heerenveen, where his father became a judge. Here he met his youth friend Eelco van Kleffens (7 November 1894, Heerenveen – 1983), who became the WW2 minister of foreign affairs and a cold war UN president from 54/55. Both men studied Law in Leiden and dissertated on the same day.
Cleveringa studied Law from 16 September 1913 till 27 June 1917 (final exams) and dissertated on 16 January 1919 cum laude with “De zakelijke werking der ontbindende voorwaarde” (The in rem effect of the escape clause) under the eminent jurist prof. Eduard Meijers, who was the father of the Dutch civil code. Soon he worked as a jurist for the Royal Netherlands Steamship Co (K.N.S.M.), publishing about the Law of the Sea.
In 1926 he became judge in Alkmaar. In 1927, he became professor in Commercial and Civil Law in Leiden, a post he would keep for 31 years, But during the German occupation in WW2, it was announced on 23 November 1940 by the Nazi authorities, that all Jewish employees of Dutch Universities were immediately fired, including his promotor Meijers. The faculty of Law in Leiden decided to protest. Cleveringa as the head of the faculty, would replace the cancelled lecture of the fired Eduard Meijers of 26 November 1940 to state their position. As he had a family, and all knew that protesting in public would result in imprisonment, others proposed to do the difficult task instead, but with permission of his wife Dien, he held his famous speech. The speech was stencilled and spread over all universities. The next day the students went on strike and Leiden university was closed. Cleveringa, was arrested and imprisoned from 27 November 1940 till summer 1941 in Scheveningen (“Oranjehotel”). From 5 January till 23 July 1944 he was kept hostage in camp Vught (SS Konzentrationslager Herzogenbusch). Augustus 1944, he became a member of the College van Vertrouwensmannen, that coordinated the Dutch resistance and should help to restore Justice after liberation and prevent chaos when the outrageous civilians would put law into their own hands.
After the war, he was asked for major political functions, but refused them, as did not like the political practice. Till 1958 he was professor in Leiden, till 1963 he was member of the High Council. On 10 May 1946 he was the promotor of Winston Churchill in Leiden. He died on 15 December 1980 in Oegstgeest.
Personal
On 22 August 1922 he married in Den Haag Hiltje Boschloo (22 April 1898, Heerenveen – 8 June 1988, Warmond). They got three daughters: T. Cleveringa, Lutgerdina Afina (Dien) Cleveringa (29. August 1926, Alkmaar; 16. June 2015, Oegstgeest) and Hiltje Cleveringa (24. September 1930, Leiden).
As a professor in Leiden, he had 33 PhD. descendants. On 18 November 2004 The Leiden University paper Mare announced that Cleveringa was elected as the the most important member of Leiden University ever, before Christiaan Huygens, Johan Thorbecke, Lorentz and Kamerlingh Onnes and many others, in a poll that closed 17 November 2004 at 1 PM.

Link to Wikipedia