Christopher Clavius
Christopher Clavius



Christopher Clavius.


Born  (15380325)25 March 1538 
Died  6 February 1612(16120206) (aged 73) 
Nationality  German 
Alma mater  University of Coimbra 
Known for  Gregorian calendar, Clavius' Law 
Scientific career  
Fields  Mathematician, astronomer 
Influences  Euclid, Pedro da Fonseca, Pedro Nunes 
Christopher Clavius (25 March 1538 – 6 February 1612^{[1]}) was a Jesuit German mathematician and astronomer who modified the proposal of the modern Gregorian calendar after the death of its primary author, Aloysius Lilius. Clavius would later write defences and an explanation of the reformed calendar, including an emphatic acknowledgement of Lilio's work. In his last years he was probably the most respected astronomer in Europe and his textbooks were used for astronomical education for over fifty years in and even out of Europe.^{[2]}
Early life
Little is known about Clavius' early life other than the fact that he was born in Bamberg in either 1538 or 1537.^{[3]} His given name is not known to any great degree of certainty—it is thought by scholars to be perhaps Christoph Clau or Klau. There are also some who think that his taken name, "Clavius", may be a Latinization of his original German name, suggesting that his name may have been "Schlüssel" (German for "key", which is "clavis" in Latin).
Clavius joined the Jesuit order in 1555. He attended the University of Coimbra in Portugal, where it is possible that he had some kind of contact with the famous mathematician Pedro Nunes (Petrus Nonius). Following this he went to Italy and studied theology at the Jesuit Collegio Romano in Rome. In 1579 he was assigned to compute the basis for a reformed calendar that would stop the slow process in which the Church's holidays were drifting relative to the seasons of the year. Using the Prussian Tables of Erasmus Reinhold and building on the work of Aloysius Lilius, he proposed a calendar reform that was adopted in 1582 in Catholic countries by order of Pope Gregory XIII and is now the Gregorian calendar used worldwide.
Within the Jesuit order, Clavius was almost singlehandedly responsible for the adoption of a rigorous mathematics curriculum in an age where mathematics was often ridiculed by philosophers as well as fellow Jesuits like Benito Pereira.^{[4]} In logic, Clavius' Law (inferring of the truth of a proposition from the inconsistency of its negation) is named after him.
He used the decimal point in the goniometric tables of his astrolabium in 1593 and he was one of the first who used it in this way in the West.^{[5]}^{[6]}
Astronomy
As an astronomer Clavius held strictly to the geocentric model of the solar system, in which all the heavens rotate about the Earth. Though he opposed the heliocentric model of Copernicus, he recognized problems with the Ptolemaic model. He was treated with great respect by Galileo, who visited him in 1611 and discussed the new observations being made with the telescope; Clavius had by that time accepted the new discoveries as genuine, though he retained doubts about the reality of the mountains on the Moon. Later, a large crater on the Moon was named in his honor.
Selected works
 Novi calendarii romani apologia. Rome, 1588
 Romani calendarii a Gregorio XIII P.M. restituti explicatio. Rome, 1603 (An explanation of the Gregorian calendar)
 Romani calendarii a Gregorio XIII P.M. restituti explicatio. (European Cultural Heritage Online)
 Romani calendarii a Gregorio XIII P.M. restituti explicatio. (University of Notre Dame)
 Commentary on Euclid, 1574
 Elementorum Libri XV. Cologne, 1627 (Published online by the Sächsischen Landesbibliothek  Staats und Universitätsbibliothek Dresden)
 Treatise of gnomonics, 1581
 Refutatio cyclometriae Iosephi Scaligeri. Mainz, 1609
 Clavius, Christoph (1992). Corrispondenza Edizione critica a cura di Ugo Baldini e Pier Daniele Napolitani. Pisa: Università di Pisa – Dipartimento di Matematica. (Critical edition of his correspondence)
Clavius' complete mathematical works (5 volumes, Mainz, 16111612) are available online .
See also
 Asteroid 20237 Clavius
 Clavius (crater), a lunar crater named after Clavius
 Clavius Base, located in Clavius crater, in both the novel and film versions of 2001: A Space Odyssey
 Aloysius Lilius
 Computus
 List of Jesuit scientists
 List of Roman Catholic scientistclerics
 Bracket (mathematics)
References
 ^ ENCYCLOPEDIA.COM Clavius, Christoph
 ^ "The books of Clavius were translated into Chinese, by one of his students Matteo Ricci "Li Madou" (15521610), and his influence for the development of science in China was crucial." Costantino Sigismondi, Christopher Clavius astronomer and mathematician
 ^ The exact year is somewhat unknown and depends on when one assumes a new year begins.
 ^ Amir Alexander (2014). Infinitesimal: How a Dangerous Mathematical Theory Shaped the Modern World. Scientific American / Farrar, Straus and Giroux. ISBN 9780374176815. , p. 69
 ^ Apparently Francesco Pellos used the decimal point in his Compendio del Abaco already around 1492 but was much less known than Clavius. Jekuthiel Ginsburg, "On the early history of the decimal point", American Mathematical Monthly 35 (1928) 347–349.
 ^ "Christopher Clavius", School of Mathematics and Statistics, University of St Andrews
 Ralf Kern, Wissenschaftliche Instrumente in ihrer Zeit. Cologne, 2010. pp. 254 – 255.
 James M. Lattis, Between Copernicus and Galileo: Christoph Clavius and the collapse of Ptolemaic cosmology. University of Chicago Press, 1994.
 Karl Christian Bruhns (1876), "Clavius, Christoph", Allgemeine Deutsche Biographie (ADB) (in German), 4, Leipzig: Duncker & Humblot, pp. 298–299
 Edmondo Lamalle (1957), "Clavius, Christoph", Neue Deutsche Biographie (NDB) (in German), 3, Berlin: Duncker & Humblot, p. 279
 Christoph Clavius, Corrispondenza, Edizione critica a cura di Ugo Baldini e Pier Daniele Napolitani, 7 volumes, Edizioni del Dipartimento di Matematica dell'Università di Pisa, Pisa, 1992
External links
 This article incorporates text from a publication now in the public domain: Herbermann, Charles, ed. (1913). . Catholic Encyclopedia. New York: Robert Appleton.
 Christopher Clavius (15371612), The Galileo Project
 O'Connor, John J.; Robertson, Edmund F., "Christopher Clavius", MacTutor History of Mathematics archive, University of St Andrews .
 Materialsammlung zur Geschichte von Ingolstadt: Rita Haub: Christoph Clavius
 Online Galleries, History of Science Collections, University of Oklahoma Libraries^{[dead link]}—High resolution images of works by and/or portraits of Christopher Clavius in JPEG and TIFF formats
 Cristoforo Clavio in the Historical Archives of the Pontifical Gregorian University
 Project Clavius On The Web. A Web platform for the works and literature of Christophorus Clavius, CNRIIT, CNRILC, APUG
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