Early life and education Pierre Weiss was born in Mulhouse the 25 March 1865, where he was the first born of Émile Weiss and Ida Schlumberger. At the age of 5,
Alsace was annexed to Germany. Weiss conducted his secondary studies at Mulhouse. He later left to continue higher education at the
Swiss Federal Institute of Technology in Zurich (ETH), where he obtained the diploma of mechanical engineer in 1887 as the first in the grade ranking of his class. At the age of majority, he decided to take the French nationality instead of the German one. In 1888, he practiced for the entry exam of the
École Normale Supérieure (ENS) at the
Lycée Saint-Louis, Paris, where he was admitted. After his years at the ENS, he remained there as a teacher assistant while in parallel he obtained his
license in physical sciences and mathematical sciences at the
Faculty of Sciences of Paris. During his time in Paris, he met several colleagues who will become famous mathematicians like
Élie Cartan,
Henri Lebesgue, and
Émile Borel, and famous physicists like
Aimé Cotton,
Jean Perrin, and
Paul Langevin. and the thesis jury comprised
Charles Friedel, and
Henry Pellatt. Pierre Weiss joined the academics that defended
Alfred Dreyfus, who was also of Alsace origin (born in Mulhouse) and another former ETH student. This position was controversial during his time at Rennes, so Weiss later preferred to teach at the
University of Lyon in 1899 due to this issue. Their daughter, Nicole, later married the French mathematician
Henri Cartan. As a widower in 1919, Pierre Weiss remarried in 1922 to physicist Marthe Klein. In 1939, Pierre Weiss followed his friend Jean Perrin to the University of Lyon where he died in 1940. == Physical description and personality ==