1537-1612

German astronomer and mathematician who supported Ptolemaic geocentricism over Copernican heliocentrisim, arguing the latter was physically impossible and contradicted scripture (1581). As Papal Astronomer, Clavius's recommended improvements to the Julian calendar (1582) and confirmed Galileo's telescopic discoveries but rejected his interpretation (1611). Known as the Euclid of the sixteenth century, he attempted to prove the parallel postulate; worked on fractions, algebra, and trigonometry; and was one of the first to use parentheses for aggregating mathematical terms.