The dramatic episode of Sundman

In 1912 the Finnish mathematical astronomer Karl Sundman published a remarkable solution to the three-body problem, of a type that mathematicians such as Poincaré had believed impossible to achieve. Although lauded at the time, the result dimmed from view as the 20th century progressed and its significance was often overlooked. This article traces Sundman’s career and the path to his achievement, bringing to light the involvement of Ernst Lindelöf and Gösta Mittag-Leffler in Sundman’s research and professional development, and including an examination of the reception over time of Sundman’s result. A broader perspective on Sundman’s research is provided by short discussions of two of Sundman’s later papers: his contribution to Klein’s Encyklopädie and his design for a calculating machine for astronomy.