Biographical Encyclopedia of Astronomers

2014 Edition
| Editors: Thomas Hockey, Virginia Trimble, Thomas R. Williams, Katherine Bracher, Richard A. Jarrell, Jordan D. MarchéII, JoAnn Palmeri, Daniel W. E. Green

Dungal of Saint Denis

  • Paul L. Butzer
  • Walter Oberschelp
  • Kerstin Springsfeld
Reference work entry

Born Probably Ireland, 2nd half of eighth century

Died Possibly Bobbio, Italy, after 827 and possibly 834

Dungal was a monk in deacon’s orders, poet, theologian, teacher, and the foremost expert on astronomy in Carolingian circles after the death of Alcuin in 804. He styles himself “exul, pauper et peregrinus.” Although some historians doubt whether the Dungal of St. Denis, of Pavia, and of Bobbio, in a putative time of four decades, are one person, the prevalent opinion is (Garrison 101) that they are one and the same (but not the same person as “Hibernicus exul”).

Dungal, whose writings show him to have been a man of unusual attainments and perhaps a son of a wealthy Scotch-Irish family, presumably left his home about 784 or somewhat later, since we find him as a recluse in St. Denis in 801. Despite his geographical and social separation from Charlemagne’s court, one may still consider him as a member (Garrison 110–112) and as a favorite of Charlemagne. He enjoyed a reputation as a teacher comparable to Alcuin, with whom he was on friendly terms and to whom he addressed some epistles. Of special interest in 810 was a rumor concerning two solar eclipses that were said to have occurred that year, one on June 5 and the other on November 30. Charlemagne sought an explanation from Dungal, whom he had already contacted in 801 in regard to philosophical notions of Fridugisus. Dungal’s answer from 811 is, in a double sense, an important document for Carolingian astronomy and certifies him as an outstanding astronomer of his time.
  1. I.

    Even though Dungal does not answer Charles’s question directly, his lengthy text is an informative primer to lunar and planetary astronomy of the time, written for the astronomical experts at the court (Eastwood 122). Dungal also discusses the classical controversy between Plato’s heliocentrism of the inner planets and Cicero’s pure geocentric view. The circulation of the inner planets Mercury and Venus with respect to the sun was an important issue at the court, as is supported by a famous Carolingian book-painting (Leiden, Aratea-Planispherium, BKO after p.480), which shows the inner planets circling around the sun (thus a step towards Tycho Brahe’s system).

  2. II.

    Dungal’s letter gives indirect information on the astronomical knowledge at the court of Charlemagne: obviously, there had been doubts at the court concerning two solar eclipses in summer 810, which were mentioned in several sources (Schowe 177/78), while lunar and solar eclipses had been observed and recorded for June 20 and November 30, 810, respectively. The occurrence of a solar and a lunar eclipse within 2 weeks and the appearance of another solar eclipse five or six lunations later seemed quite unusual. As a matter of fact, according to present knowledge (NASA), solar eclipses took place both on June 5 and July 5, 810, but they were not visible in Europe. Thus they must have been reconstructed according to some unknown rule (Newton 595/96). Since there was another “false” solar eclipse recorded for April 27, 811 (Springsfeld 242), which is six lunations after November 30, 810, the question arises as to how such a collection of hypothetic eclipses could be conceived.


There is an explanation: Pliny (Naturalis Historiae II, 57) mentions the possibility of a lunar and a solar eclipse taking place within 2 weeks and describes – relying on Hipparcos – further possible solar eclipses some lunations later. The eclipses undoubtedly observed by the Carolingians fit into the schema of Plinius. In addition the solar eclipses in question could be deduced from Pliny’s remark. But Dungal in his letter explicitly complains for not having Pliny’s natural history at hand. This is why hefails to answer Charles’ question directly. We conclude Pliny’s remark was the very source of “calculating” or reconstructing the “wrong” eclipses at the court, where Pliny’s text was in the library. This consequence supplements investigations by Eastwood and Graßhoff about Pliny’s strong influence on Carolingian astronomy.

After Charlemagne’s death in 814, Dungal was mentioned 823 in a “capitulary” of Lothair I and 825 in an imperial decree by which he was appointed “master” of the new cathedral school at Pavia, with jurisdiction over 11 subordinate schools in different cities of northern Italy. At the request of Emperor Louis the Pious, he wrote in 827/28 a refutation of teachings of Claudius of Turin, a pupil of Felix of Urgell and an exegete, dealing with Western iconoclasm. Since he bequeathed his valuable library of some 27 volumes to the Irish monastery at Bobbio (in the Trebbia valley, founded 614), among them the “Antiphonary of Bangor,” it is inferred that he spent his last days there. The date of his death is unknown.

Selected References

  1. Butzer, Paul L., Kerner, Max and Oberschelp, Walter (eds.) (1997), [BKO], Charlemagne and his Heritage, 1200 Years of Civilization and Science in Europe, Vol. I, Brepols.Google Scholar
  2. Dungal: Migne (ed.) (1864), Dungali Reclusi epistulae de duplici solis eclipse anno 810, Patrologia Latina vol. 105: col. 447–458. Also in Dümmler (ed.), (1895), MGH, Epistolae 4, 570–578 (Reprint 1994).Google Scholar
  3. Eastwood, Bruce (1994), The astronomy of Macrobius in Carolingian Europe: Dungal’s letter of 811 to Charles the Great. Early medieval Europe 3, 117–34.CrossRefGoogle Scholar
  4. Eastwood, Bruce, Graßhoff, Gerd (2004), Planetary diagrams for Roman astronomy, in Medieval Europe, Trans. American Philos. Soc. 94, Pt. 3.Google Scholar
  5. Eastwood, Bruce (2007), Ordering the Heavens – Roman Astronomy and Cosmology in the Carolingian Renaissance. History of Science and Medicine Library, Vol. 4, Series Medieval and Early Modern Science.Google Scholar
  6. Ferrari, Mirella, (1993), Dungal, Dizionario Biografico degli Italiani, Vol. 42.Google Scholar
  7. Garrison, Mary (1997), The English and the Irish at the court of Charlemagne, in BKO, 97–123.Google Scholar
  8. NASA, Five Millennium Catalog of Solar Eclipses (Fred Espenak), http// Scholar
  9. Newton, Robert R. (1972), Medieval chronicles and the rotation of the earth, The John Hopkins Univ. Press (Reprint 1990).Google Scholar
  10. Schowe, Justin (1984), Chronology of eclipses and comets AD 1–1000, The Boydell Press.Google Scholar
  11. Springsfeld, Kerstin (2002), Alkuins Einfluss auf die Komputistik zur Zeit Karls des Großen, Franz Steiner Verlag.Google Scholar

Copyright information

© Springer Science+Business Media New York 2014

Authors and Affiliations

  • Paul L. Butzer
    • 1
  • Walter Oberschelp
    • 2
  • Kerstin Springsfeld
    • 3
  1. 1.RWTH AachenAachenGermany
  2. 2.RWTH Aachen, Lehrstuhl Informatik VIIAachenGermany
  3. 3.AachenGermany