Leiden University alumni

Willem-Alexander (Dutch: [ˈʋɪləm aːlɛkˈsɑndər]; Willem-Alexander Claus George Ferdinand; born 27 April 1967) is King of the Netherlands.
Willem-Alexander was born in Utrecht during the reign of his maternal grandmother, Queen Juliana, as the eldest child of Princess Beatrix and Prince Claus. He became Prince of Orange as heir apparent upon his mother's accession on 30 April 1980. He went to public primary and secondary schools in the Netherlands, an international sixth-form college in Wales, served in the Royal Netherlands Navy, and studied history at Leiden University. He married Máxima Zorreguieta Cerruti in 2002, and they have three daughters: Catharina-Amalia, Alexia, and Ariane. Willem-Alexander succeeded his mother as monarch upon her abdication in 2013.
Willem-Alexander is interested in sports and international water management issues. Until his accession to the throne, he was a member of the International Olympic Committee (1998–2013), chairman of the Advisory Committee on Water to the Dutch Minister of Infrastructure and the Environment (2004–2013), and chairman of the Secretary-General of the United Nations' Advisory Board on Water and Sanitation (2006–2013).

Hendrik Antoon Lorentz (; 18 July 1853 – 4 February 1928) was a Dutch physicist who shared the 1902 Nobel Prize in Physics with Pieter Zeeman for the discovery and theoretical explanation of the Zeeman effect. He derived the Lorentz transformation of the special theory of relativity, as well as the Lorentz force, which describes the combined electric and magnetic forces acting on a charged particle in an electromagnetic field. Lorentz was also responsible for the Lorentz oscillator model, a classical model used to describe the anomalous dispersion observed in dielectric materials when the driving frequency of the electric field was near the resonant frequency, resulting in abnormal refractive indices.
According to the biography published by the Nobel Foundation, "It may well be said that Lorentz was regarded by all theoretical physicists as the world's leading spirit, who completed what was left unfinished by his predecessors and prepared the ground for the fruitful reception of the new ideas based on the quantum theory." He received many other honours and distinctions, including a term as chairman of the International Committee on Intellectual Cooperation, the forerunner of UNESCO, between 1925 and 1928.

Jean Abraham Chrétien Oudemans (Amsterdam, 16 December 1827 – Utrecht, 14 December 1906) was a Dutch astronomer. He was the director of the Utrecht Observatory from 1875 until 1898, when he retired.
Oudemans was born in Amsterdam, son of the poet, teacher and philologist Anthonie Oudemans Sr. and Jacoba Adriana Hammecker. He entered Leiden University when he was just 16 as a student of the noted astronomer Frederik Kaiser. He became a high school teacher in Leiden when he was just 19 (1846). The next six years he worked on his dissertation on the determination of the latitude of Leiden. Next he studied asteroids and variable stars, meanwhile hoping for an academic appointment. In 1855 he became member of the Royal Netherlands Academy of Arts and Sciences.
He married Pauline Adriana Verdam (the daughter of a well-known mathematics professor Gideon Jan Verdam ) in 1856. In the same year he was appointed a professor at Utrecht University and became the first director of its observatory. However, his interest drew him towards geography. He traveled to the Dutch East Indies as head surveyor, and worked in that capacity for 18 years, publishing his works on the triangulation of the island of Java in six books.In 1874 he organized an astronomical expedition to the island of Réunion to observe the transit of Venus but, due to bad weather, the results were disappointing.Oudemans crater on Mars was named in his honor.
A brother was the botanist Corneille Antoine Jean Abram Oudemans. One of his sons was Anthonie Cornelis Oudemans Jzn, one of the fathers of cryptozoology.

Klaus Paul Alfred Clusius (19 March 1903 – 28 May 1963) was a German physical chemist from Breslau (Wrocław), Silesia. During World War II, he worked on the German nuclear energy project, also known as the Uranium Club; he worked on isotope separation techniques and heavy water production. After the war, he was a professor of physical chemistry at the University of Zurich. He died in Zurich.

Lucien Sophie Albert Marie von Römer (23 August 1873 – 23 December 1965) was a Dutch physician, botanist and writer. He often wrote about homosexuality, and argued that it was an innate characteristic. He practiced medicine in the Dutch East Indies (later Indonesia) in his later life. His views parallel those of psychiatrist Sigmund Freud on this topic.

Gustaaf Adolf Frederik Molengraaff (27 February 1860 – 26 March 1942) was a Dutch geologist, biologist and explorer. He became an authority on the geology of South Africa and the Dutch East Indies.
Gustaaf Molengraaff studied mathematics and physics at Leiden University. From 1882 he studied at Utrecht University. As a student he made his first journey overseas when he joined the 1884–1885 expedition to the Dutch Antilles led by Willem Frederik Reinier Suringar and Karl Martin. He became PhD with a thesis on the geology of Sint Eustatius. He studied crystallography in Munich, where he also took the opportunity to study the geology of the Alps nearby.
In 1888 Molengraaff took a job as a teacher at the University of Amsterdam. Before his assignment courses in geology were given by the chemist Jacobus Henricus van 't Hoff. During his assignment in Amsterdam, Molengraaff travelled to South Africa to study gold deposits (1891) and to Borneo (1894) where he explored large parts of the inland. Teaching at Amsterdam was not to his liking, because there were too little materials and students available.
In 1897 Molengraaff became "state geologist" of the Transvaal Republic. His task was to start the geological survey of the Transvaal. While mapping the Transvaal he discovered the Bushveld complex. In 1900 he got involved in the Second Boer War and had to return to the Netherlands. This gave him time to write a report on the geology of the Transvaal, and travel to Celebes, where he (again) studied gold deposits.
Due to his reputation as a geologist he could return to South Africa in 1901 to work as a geological consultant. One of his assignments was to describe the newly found Cullinan diamond for the Central Bank of South Africa. Meanwhile the Boer War still had his attention. One of his ideas was to give each soldier a small tin identity card, which later became practice in armies around the world.
In 1906 he became professor at Delft University and this time he got enough resources and students to make his work successful. The same year he became member of the Royal Netherlands Academy of Arts and Sciences. In 1910-1911 he led a geological expedition to Timor. His research at Delft was mainly on the material collected during that expedition, and on the geology of the Netherlands. In 1922 he was a guide, along with A L Hall, of the Shaler Memorial Expedition to South Africa, organized by Harvard University. On the expedition he met Alexander Du Toit, both geologists were among the (at that time rare) supporters of Alfred Wegeners' continental drift theory.
Molengraaff was a close friend of W. F. Gisolf, who named his youngest son after him but died in a Japanese concentration camp.
Molengraaff retired in 1930.

Cornelis Adriaan Lobry van Troostenburg de Bruyn (1 January 1857 – 23 July 1904) was a chemist from the Netherlands.

Cornelis Jacobus (Cor) Gorter (14 August 1907, Utrecht – 30 March 1980, Leiden) was a Dutch experimental and theoretical physicist. Among other work, he discovered paramagnetic relaxation and was a pioneer in low temperature physics.

Robert Hans van Gulik (Chinese: 髙羅佩; pinyin: Gāo Luópèi, 9 August 1910 – 24 September 1967) was a Dutch orientalist, diplomat, musician (of the guqin), and writer, best known for the Judge Dee historical mysteries, the protagonist of which he borrowed from the 18th-century Chinese detective novel Dee Goong An.

Gilles Quispel (30 May 1916 – 2 March 2006) was a Dutch theologian and historian of Christianity and Gnosticism. He was professor of early Christian history at Utrecht University.
Born in Rotterdam, after finishing secondary school in Dordrecht, Quispel studied classical philology from 1934 to 1941 at the Leiden University. At Leiden he also began to study theology, which he continued at the University of Groningen. Quispel completed his doctoral work in 1943 at Utrecht University with a dissertation examining the sources utilized in Tertullian's Adversus Marcionem. He devoted study to several Gnostic systems, particularly Valentinianism. In 1948-1949 he spent a year in Rome as a Bollingen fellow and was appointed professor of the history of the early Church at Utrecht University in 1951. Quispel served as a visiting professor at Harvard University in 1964-1965 and at the Katholieke Universiteit Leuven in 1968. He was engaged in first editing Nag Hammadi Codex I (the "Jung Codex") and devoted attention to the Nag Hammadi Library and particularly to the Gospel of Thomas throughout the rest of his career. Quispel also made contributions to the study of early "Jewish-Christian" traditions as well as Tatian's Diatessaron (a second-century gospel harmony). He died in El Gouna, Egypt.