**Enno Heeren Dirksen** was a German mathematician important in the development of Berlin University as a world-class mathematical centre.

- Frisia, the area where Enno was born, was divided into Friesland, East Friesland and North Friesland in 1815.
- It is possible that Enno lived for a while in Hamswehrum, about 7 km south west of Eilsum (and still within 15 km of Emden), as he was growing up since he had relations there and a number of older biographies incorrectly gave Hamswehrum as his place of birth.
- Between 1803 and 1807 Dirksen received private lessons in mathematics, physics, astronomy and navigation from Cornelius Voorn who was a teacher at the Emden Navigation School.
- At this stage Voorn hoped that Dirksen would succeed him as teacher at the Navigation School.
- After completing this course of private lessons, Dirksen became a teacher in Hatzum, about 10 km south east of Emden.
- Soon after he began teaching in Hinte, Jabbo Oltmanns, a mathematician who worked in Emden, suggested that Dirksen should study mathematics at Göttingen University to improve his mathematical skills.
- Dirksen studied for his doctorate advised by Mayer and Thibaut, although he also assisted Gauss in calculating the orbits of comets and asteroids.
- In October 1819 Dirksen had requested support from the ministry in Hanover so that he could spend a year in Berlin working at the Academy of Architecture with Johann Albert Eytelwein.
- Dirksen assisted Bode both in making observations and in doing mathematical computation and he habilitated at Berlin University on 6 May 1820 as an expert in astronomy in the Mathematics Department.
- On 26 August 1820 the Prussian Ministry appointed Dirksen as an extraordinary professor in Berlin University and four years later, on 18 June 1824, he was appointed as a full Professor of Mathematics.
- Dirksen was elected to the Berlin Academy of Sciences on 9 June 1825 and over the next twenty plus years he served both the University and the Academy.
- We cannot rate Dirksen highly as a research mathematician but his role in the development of Berlin University as a world-class mathematical centre is substantial.
- Finally we note that his somewhat old-fashioned approach to mathematics at a time when new techniques were rapidly being developed led to arguments between Dirksen and various colleagues.

Born 3 January 1788, Eilsum, Frisia, Germany. Died 16 July 1850, Paris, France.

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Astronomy, Origin Germany

**O’Connor, John J; Robertson, Edmund F**: MacTutor History of Mathematics Archive