History of Astronomy : Persons : Persons (J) : Jordanus de Nemore

Jordanus de Nemore

Jordanus de Nemore, along with Leonardo Fibonacci, was the dominant mathematician of the first half of the 13th century. He is best known for his works on mechanics (statics) but he also wrote influential works on arithmetic, geometry and algebra. Little is known about Jordanus' life. His name, de Nemore (literally of the forest or Forester) suggests he was from a wooded area. Some scholars feel Jordanus de Nemore and Jordanus of Saxony, second Grand Master of the Dominican order, are the same person. If this is so, Jordanus was born in the area of Mainz and was educated in Paris. He was elected Grand Master in 1222 and died in a shipwreck on 13 February 1237 while returning from the Holy Land.

Jordanus' works are distinguished by rigorous proofs. Six works that are definitely from Jordanus and four that are possibly his.

His greatest legacy was in mechanics (statics): "Elementa super demonstrationem ponderum and possibly De ratione ponderis".

"Liber phylotegni de triangulus". Jordanus' major geometrical work.

"De elementis arismetice artis". 400 propositions on arithmetic that became the standard source for theoretical arithmetic in the Middle Ages.

"Tractatus minutiarum". Fractions.

"De numeris datis". A formal Euclidian style (i.e. axioms, definitions, propositions) treatise on algebra.

"De plana spera". A formal geometric treatise on the stereographic projectio, the projection used on the planispheric astrolabe.

Possible works:

"De proportionibus". Probably a translation of an Arabic work.
"Isoperimetra". Figures with equal perimeters, probably of Greek origin.
"Demonstrationes pro astrolapsu". Sometimes attributed to Campanus of Novara.
"Preexercitamina". Known only from a reference in another of Jordanus texts.
"Elementa super demonstrationem ponderum and possibly De ratione ponderis".


Hughes, Barnabas B.: Biographical Information on Jordanus de Nemore to Date, Janus, 62 (1975): 151-156.

Poggendorff, J. C.: Biographisch-literarisches Handwörterbuch zur Geschichte der exacten Wissenschaften. Zweiter Band. Leipzig, 1863, p. 267.

Thomson, Ron B.: Jordanus de Nemore and the Mathematics of Astrolabes: De Plana Spera. Toronto: Pontifical Institute of Mediaeval Studies, 1978.

More information on Jordanus de Nemore

Text written by James E. Morrison, astrolabe@ntplx.net

Edited and HTML version by Wolfgang R. Dick Created: 28 Jan 1997. Latest update: 7 Jan 1998