Christoph Clau, mathematician and astronomer, whose most important achievement related to the reform of the calendar under Gregory XIII ; born at Bamberg, Bavaria, 1538; died at Rome, 12 February, 1612. The German form of his name was latinized into "Clavius". He entered the Society of Jesus in 1555 and his especial talent for mathematical research showed itself even in his preliminary studies at Coimbra. Called to Rome by his superiors as teacher of this branch of science at the well-known Collegium Romanum, he was engaged uninterruptedly there until his death. the greatest scholars of his time, such men as Tycho Brahe, Johann Kepler, Galileo Galilei, and Giovanni Antonio Magini, esteemed him highly. He was called the "Euclid of the sixteenth century"; and even his scientific opponents, like Scaliger, said openly that they would rather be censured by a Clavius than praised by another man. There has, however, been no lack of persistent disparagement of Catholic scholars even down to our own times; and therefore much that is inexact, false, and mythical has been put into circulation about Clavius, as for example that he was originally named "Schlüssel" ( clavis , "key"), that he was appointed a cardinal, that he met his death by the thrust of a mad bull, etc. His relations with Galilei, with whom he remained on friendly terms until his death, have also been often misrepresented. The best evidence of the actual achievements of the great man is presented by his numerous writings, which at the end of his life he reissued at Mainz in five huge folio volumes in a collective edition under the title, "Christophori Clavii e Scoietate Jesu opera mathematica, quinque tomis distributa". The first contains the Euclidian geometry and the "Spheric" of Theodosius (Sphaericorum Libri III); the second, the practical geometry and algebra; the third is composed of a complete commentary upon the "Sphaera" of Joannes de Sacro Bosco (John Holywood), and a dissertation upon the astrolabe; the fourth contains what was up to that time the most detailed and copious discussion of gnomonics, i.e. the art of constructing all possible sun-dials; finally, the fifth contains the best and most fundamental exposition of the reform of the calendar accomplished under Gregory XIII.
Many of these writings had already appeared in numerous previous editions, especially the "Commentarius in Sphaeram Joannis de Sacro Bosco" (Rome, 1570, 1575, 1581, 1585, 1606; Venice, 1596, 1601, 1602, 1603, 1607, Lyons, 1600, 1608, etc.); likewise the "Euclidis Elementorum Libri XV" (Rome 1574, 1589, 1591, 1603, 1605; Frankfort 1612). After his death also these were republished in 1617, 1627, 1654, 1663, 1717, at Cologne, Frankfort, and Amsterdam, and were even translated into Chinese. In his "Geometria Practica" (1604) Clavius states among other things a method of dividing a measuring scale into subdivisions of any desired smallness, which is far more complete than that given by Nonius and must be considered as the precursor of the measuring instrument named after Vernier, to which perhaps the name Clavius ought accordingly to be given. The chief merit of Clavius, however, lies in the profound exposition and masterly defence of the Gregorian calendar reform, the execution and final victory of which are due chiefly to him. Cf. "Romani calendarii a Gregorio XIII restituti explicatio" (Rome, 1603); "Novi calendarii Romani apologia (adversus M. Maestlinum in Tübingensi Academiâ mathematicum)" (Rome, 1588). Distinguished pupils of Clavius were Grienberger and Blancanus, both priests of the Society of Jesus.
More Catholic Encyclopedia
Browse Encyclopedia by Alphabet
The Catholic Encyclopedia is the most comprehensive resource on Catholic teaching, history, and information ever gathered in all of human history. This easy-to-search online version was originally printed in fifteen hardcopy volumes.
Designed to present its readers with the full body of Catholic teaching, the Encyclopedia contains not only precise statements of what the Church has defined, but also an impartial record of different views of acknowledged authority on all disputed questions, national, political or factional. In the determination of the truth the most recent and acknowledged scientific methods are employed, and the results of the latest research in theology, philosophy, history, apologetics, archaeology, and other sciences are given careful consideration.
No one who is interested in human history, past and present, can ignore the Catholic Church, either as an institution which has been the central figure in the civilized world for nearly two thousand years, decisively affecting its destinies, religious, literary, scientific, social and political, or as an existing power whose influence and activity extend to every part of the globe. In the past century the Church has grown both extensively and intensively among English-speaking peoples. Their living interests demand that they should have the means of informing themselves about this vast institution, which, whether they are Catholics or not, affects their fortunes and their destiny.
Browse the Catholic Encyclopedia by Topic
Copyright © Catholic Encyclopedia. Robert Appleton Company New York, NY. Volume 1: 1907; Volume 2: 1907; Volume 3: 1908; Volume 4: 1908; Volume 5: 1909; Volume 6: 1909; Volume 7: 1910; Volume 8: 1910; Volume 9: 1910; Volume 10: 1911; Volume 11: - 1911; Volume 12: - 1911; Volume 13: - 1912; Volume 14: 1912; Volume 15: 1912
Catholic Online Catholic Encyclopedia Digital version Compiled and Copyright © Catholic Online