REGIOMONTANUS, rē"jĭ-ŏ-mŏn-tā'nŭs,
German astronomer, whose real name was
Johann Müller, but who assumed that of
Regiomontanus, in allusion to the place of his
birth, Königsberg (Kings Mountain),
Franconia: b. 6 June 1436; d. Rome, 6 July 1476.
Having received a classical education at Leipzig,
be placed himself under Purbachius
(Georg von Purbach), the professor of mathematics
at Vienna, and under him became one
of the first astronomers of that age. With
Purbachius he accompanied Cardinal Bessarion
to Rome in 1461, where Beza gave him further
instruction in Greek literature, and he now
completed a new abridgment in Latin of the
‘Almagest’ of Ptolemy (1496), correcting many
errors in the former translation, made by
George of Trebizond. In 1471 he built an
observatory at Nuremberg and established a press,
but after three years returned to Rome on the
invitation of Sixtus IV, who employed him in
the reformation of the calendar and rewarded
his services by raising him to the bishopric of
Ratisbon (1475). He died, according to some,
of the plague, according to others by poison
administered by the son of George of Trebizond
out of revenge for his having exposed the
errors of his father. Regiomontanus was the
first in Germany to apply himself to the cultivation
of the neglected science of algebra. He
made great improvements in trigonometry, into
which he introduced the use of tangents. His
refutation of a supposed discovery of the
quadrature of the circle and numerous writings on
various subjects of natural philosophy display
extensive learning and great acuteness. His
astronomical observations from 1475 to 1506
(‘Ephemerides’) are very accurate. Among
his other works ‘Kalendarium’ (about 1474),
‘De Reformatione Kalendarii’ (1489); ‘De
Cometæ Magnitudine Longitudineque’ (1531);
‘De Triangulis Omnimodis’ (1533); ‘Tabulæ
Directionum Prejectionumque in Nativitatibus
multum utiles’ (1585). Consult Gunther,
‘Johannes Müller’ (in the ‘Allgemeine deutsche
Biographie,’ Vol. XXII, 1855); also Ziegler,
‘Regiomontanus als, geistiger Vorläufer des
Columbus’ (1874).
