1907 – Born on the 18th of April in Helsinki, Finland.
1924 – He studied at Helsinki University, Finland.
1928 – He graduated, having studied under Ernst Lindelof and Rolf Nevanlinna.
1929 – He assisted Nevanlinna with his work on Denjoy’s conjecture.
– He was appointed lecturer in mathematics at the Abo Akademi (in Turku).
1930 – He completed his doctorate.
1935 – He went to Harvard University, USA.
1936 – He was one of the first two people to be awarded the Fields Medal.
1938 – He returned to Finland to take up a post at the University of Helsinki.
1944 – He was offered a post at the Swiss Federal Institute of Technology at Zurich.
1945 – He accepted a job at the Swiss Federal Institute of Technology at Zurich.
1964 – He was William Caspar Graustein Professor of Mathematics.
1968 – He was awarded the Vihuri Prize.
1977 – He returned to work at Harvard where he remained until he retired.
1981 – He received an award the "Wolf Prize in Mathematics".
1996 – He died on the 11th of October.