Erhard Weigel

Who was Erhard Weigel?

Erhard Weigel was a German mathematician, astronomer and philosopher.

He earned his Ph.D. from the University of Leipzig. From 1653 until his death he was professor of mathematics at Jena University. He was the teacher of Leibniz in 1663, and other notable students. He also worked to make science more widely accessible to the public, and what would today be considered a populariser of science. Through Leibniz, Weigel is the intellectual forefather of a long tradition of mathematicians that connects a great number of professionals to this day. The Mathematics Genealogy Project lists more than 50,000 "descendants" of Weigel's, including Lagrange, Euler, Poisson and several Fields Medalists.

He concurred with Jakob Ellrod's "Mittel-Calendar", and with the advocacy of Leibniz and others, that the date of Easter should be based on the astronomical measurement of the spring equinox and the next full moon. He followed Jakob Ellrod to the Imperial Diet in Regensburg to advocate the use of the Mittel-Calendar or New Gregorian calendar.

The crater Weigel on the Moon is named after him. In 1999 a colloquium was held in Jena on the 300th anniversary of his death.