Petrus de Dacia (mathematician)
Petrus de Dacia, also called Philomena and Peder Nattergal (Peter Nightingale), was a Danish scholar who lived in the 13th century. He worked mainly in Paris and Italy, writing in Latin. He published a calendar of new moon dates for the years 1292 - 1367. In 1292, he published a book on mathematics that contained a new methods for the calculation of cubic roots. He also described a mechanical instrument to predict solar and lunar eclipses as seen from Paris.
- Corpus Philosophorum Danicorum Medii Aevi vol. X, ed. Fritz Saaby Pedersen. Copenhagen 1983.
- Pedersen, Olaf (in: Complete Dictionary of Scientific Biography. 2008. http://www.encyclopedia.com/doc/1G2-2830903368.html)
- Rasch, G. (1932) Petrus de Dacia, pp. 12-15 in: Meisen, V. Prominent Danish Scientists through the Ages. University Library of Copenhagen 450th Anniversary. Levin & Munksgaard, Copenhagen