Clavius, Christoph

CLAVIUS, CHRISTOPH. - Celebrated Jesuit mathematician, b. at Bamberg in 1538, d. at Rome on 6 February 1612. Having entered the Society at Rome in 1555, he studied at Coimbra in Portugal and then held the chair of mathematics at the Roman College almost without interruption from 1565 until his death. He took an active part in the preparation of the Society's Ratio studiorum and strongly influenced the flourishing development that the mathematical sciences then took on within the Order. His works, intended mainly for teaching, ran to numerous reprints: In sphaeram Ioannis de Sacro Bosco commentarius (Rome 1570); Gnonomicae libri VIII (ibid. 1581); Epitome arithmeticae practicae (ibid. 1583); Astrolabium (ibid. 1593); Computus ecclesiasticus (ibid. 1597); Geometria practica (ibid. 1604); Algebra (ibid. 1608). The most renowned, Euclidis elementorum libri XV (ibid. 1574, with a book XVI by C.), had a wide influence even outside Europe; it was translated, for example, into Chinese by Fr. Matteo Ricci, formerly a pupil of C. A fine collected edition was made of it: Opera mathematica (5 vols. in fol., Mainz 1612). C. earned the name of "Euclid of the 16th century," not for originality of discoveries or theories, but for the wonderful gift of synthesis with which he clarified and unified the whole acquisition of the mathematical sciences of his time. He was also an incomparable teacher and remained in scientific correspondence not only with his former pupils, but with the leading scientists of his time. His relations with Galileo, whose first discoveries he followed and supported with benevolence, are well known.

C. was one of the principal collaborators in the Gregorian reform of the calendar (1577-82) and it seems that its definitive drafting is owed to him. He was then charged by Gregory XIII and by Clement VIII with explaining the new calendar and spreading it against the attacks of the Protestants: Novi calendarii romani apologia adversus Michaelem Maestlinum (Rome 1588); Romani calendarii a Gregorio XIII P. M. restituti explicatio S. D. N. Clementis VIII P. M. iussu edita (ibid. 1595); he wrote other apologies against Scaliger (ibid. 1595 and 1609) and against Georg Germanus (ibid. 1610). The monograph on C. that he would deserve is still lacking.

Edmondo Lamalle