At the initiative of Paul Ehrenfest, a special chair in Leiden was created for Albert Einstein, enabling him to come to our university for short periods of his choosing. On October 27, 1920, Einstein began his new position with an inaugural address on ether and relativity theory. The yearly visits stopped when Einstein fled Europe in 1933. The position was formally terminated by the German occupation.
Reminiscenses of Einstein's visits to Leiden are described elsewhere on this site. Here we present the three Einstein manuscripts preserved in our archives. Read the story of their discovery in Dutch and in English. You might also be interested in the papers of Alexander Friedmann, discovered together with the Einstein papers.
Manuscript in Einstein's handwriting (dated December 1924), with editorial markup. It was evidently used by Einstein to correct the page proofs in early 1925 and left behind in Leiden after his February visit. The publication is in the proceedings of the Berlin Academy of Sciences. (The reprint shown here was Ehrenfest's copy.) Page 2 of the manuscript reports the last scientific discovery of Einstein's career: the prediction of the new state of matter now called the Bose-Einstein condensate. (The 2001 Nobel prize went to its experimental observation in a cold dilute gas.)
The manuscript follows up on an earlier article, which is preserved in manuscript at the Hebrew University of Jerusalem. That earlier work, however, does not yet contain the prediction of the condensation phenomenon.
Typed manuscript with handwritten formulas and corrections. The publication (co-authored with Marcel Grossmann) appeared in 1914 in the Zeitschrift für Mathematik und Physik. It reports on the heroic struggle to find generally covariant equations for the gravitational field, in which Einstein would finally succeed a year later. The handwriting of the formulas and corrections appears to be that of Grossman and Einstein, respectively. The typescript contains annotations by Ehrenfest ("does it make sense to separate x and t"), who had intensive discussions with Einstein on this problem. Einstein may have left the document in Leiden upon his visit of March 1914.
Page proof, with corrections, of Einstein's publication on the "Propagation of Sound in Partly Dissociated Gases", which appeared in 1920 in the Proceedings of the Berlin Academy of Sciences. The last two pages of the proof are crossed out and replaced by a sheet in Einstein's handwriting. (Here is an analysis of this replacement.)
Full-size scans of the Einstein documents are accessible here. These were found together with a collection of letters, notes, and some annotated articles, which is accessible here. The Ehrenfest archive has been transferred to the Museum Boerhaave.