The 1859 Space Weather Event: Then and Now

The 1859 space weather event, combining the first solar flare ever reported with arguably the largest geomagnetic storm ever observed, provided a dramatic opening to a new area of Sun-Earth studies. Here I describe solar science at the time of the discovery of the flare, recount the observation, and trace the developments that led to the correct interpretation of the 1859 solar-errestrial event by Bartels in 1937. A fast forward takes us to the present time when advances in modeling and increasing concern with space weather have prompted renewed interest in a classic observation.