Adriaan van Roomen (29 September 1561 – 4 May 1615), also known as Adrianus Romanus, was a mathematician, professor of medicine and medical astrologer from the Duchy of Brabant in the Habsburg Netherlands who was active throughout Central Europe in the late 16th and early 17th centuries. As a mathematician he worked in algebra, trigonometry and geometry; and on the decimal expansion of pi. He solved the Problem of Apollonius using a new method that involved intersecting hyperbolas. He also wrote on the Gregorian calendar reform.

Life

Van Roomen was born in Leuven, the son of Adriaan Van Roomen and Maria Van Den Daele. He was educated partly in Leuven and partly After studying at the Jesuit College in Cologne, also attending the University of Cologne where he began his study of medicine.^[1] He also briefly studied medicine at Leuven University. Roomen was professor of mathematics and medicine at Louvain from 1586 to 1592. He met Kepler, and discussed with François Viète two questions about equations and tangencies. He then spent some time in Italy, particularly with Clavius in Rome in 1585. His publication of 1595, Parvum theatrum urbium, contained Latin verse on the cities of Italy (possibly written by Thomas Edwards).^[2]

In June 1593 Van Roomen became the inaugural professor of medicine at the newly refounded University of Würzburg.^[1] He was also appointed physician in ordinary to the court of Rudolf II.^[1] From around 1595 to 1603 he produced calendars, almanacs and prognostications published under the patronage of Julius Echter, prince-bishop of Würzburg.^[3] At the same time, he served as mathematician of the king of Poland and become famous for the computation of the value of pi to sixteen decimals,^[4][5] surpassing François Viète who had arrived at ten digits.^[6] After being widowed he was ordained to the priesthood in 1604 and on 8 October 1608 was installed as a canon of the collegiate church of St John the Evangelist in Würzburg.^[1]

His Mathesis Polemica, published in Frankfurt in 1605, explained the military applications of mathematics. In June 1610 he was in Prague, after which he travelled to Poland at the invitation of Jan Zamoyski to give public lectures on mathematics at Zamość in Red Ruthenia. He made the return journey via Hungary, arriving back in Würzburg at the end of 1611.^[1]

Struggling with health problems, Van Roomen undertook a journey to Spa to take the waters but died en route at Mainz in the arms of his son, who was travelling with him.^[1]