1923 – He was born in La Chaux-de-Fonds, on the 21st of May.
– He studied at the ETH Zürich.
1949 – He went to Paris, he applied the Leray spectral sequence to the topology of Lie groups and their classifying spaces, under the influence of Leray and Henri Cartan.
1957-1993 – He became permanent professor at the Institute for Advanced Study in Princeton, New Jersey.
– He collaborated with Jacques Tits in fundamental work on algebraic groups, and with Harish-Chandra on their arithmetic subgroups.
– He published his work on the history of Lie groups.
2003 – He died on the 11th of August in Princeton, NJ of cancer at age 80.