Adriaan Anthonisz

Adriaan Anthonisz (also known as Adriaen Anthonisz of Alcmaer) (1527–1607)[1][2][3] was a Dutch mathematician, surveyor, cartographer, and military engineer who specialized in the design of fortifications. As a mathematician Anthonisz calculated in 1585 the ratio of a circle's circumference to its diameter, which would later be called pi.[2]

Statue of Adriaen Anthonisz by John Bier [nl]


Anthonisz served as burgomaster (mayor) of Alkmaar in the Netherlands from 1582.[4]

Adriaan fathered two sons, and named them both Metius (from the Dutch word meten, meaning 'measuring', 'measurer', or surveyor). They each became prominent members of society.[5] Adriaan Metius (9 Dec 1571 – 6 Sep 1635) was a Dutch geometer and astronomer. Jacob Metius worked as an instrument-maker and a specialist in grinding lenses and applied for patent rights for the telescope a few weeks after Middelburg spectacle-maker Hans Lippershey tried to patent the same device.[6]


In 1585 Anthonisz discovered that the ratio of a circle's circumference to its diameter, later called pi, approximated the fractional value of 355/113. His son Adriaan Metius later published his father's results, and the value 355/113 is traditionally referred to as Metius' number'.[7][8]

He is regarded as one of the first military engineers to apply the principles of the Dutch fortification system.[9]

Some of his professional accomplishments included mapping the Berger lake and expanding and fortifying Naarden and Muiden.[10]


  1. ^ Charles Joseph Singer (1921). Studies in the History and Method of Science: Singer, Charles. Greek biology and its relation to the rise of modern biology. Clarendon Press.
  2. ^ a b J.L. Berggren; Jonathan Borwein; Peter Borwein (13 January 2014). Pi: A Source Book. Springer. pp. 291–. ISBN 978-1-4757-4217-6.
  3. ^ Mathematics Magazine. Mathematical Association of America. 1949.
  4. ^ Christopher Duffy (15 April 2013). Siege Warfare: The Fortress in the Early Modern World 1494-1660. Routledge. pp. 82–. ISBN 978-1-136-60786-8.
  5. ^ Harold John Cook; Sven Dupré (2012). Translating Knowledge in the Early Modern Low Countries. LIT Verlag Münster. pp. 273–. ISBN 978-3-643-90246-7.
  6. ^ "Non-Existent Domain". Retrieved 2016-04-20.
  7. ^ "Archived copy". Archived from the original on November 1, 2005. Retrieved August 30, 2005.CS1 maint: archived copy as title (link)
  8. ^ Royal Institution of Great Britain (1831). The Journal of the Royal Institution of Great Britain. John Murray. pp. 320–.
  9. ^ Koster, Fortificate – Ideaal en Werkelijkheid (PDF),, pp. 217–218, archived from the original (PDF) on 2011-11-18, retrieved 2016-04-11
  10. ^ "The Galileo Project". Rice University. Retrieved 9 May 2016.