Who first obtained the field equations of general relativity: Einstein or Hilbert? For many years this was the subject of debate! Hilbert's paper on the subject was published after Einstein's paper appeared, but he _submitted_ it five days earlier than Einstein.

A common narrative among physicists was that Hilbert and Einstein obtained more or less the same result in parallel, with Hilbert submitting first but Einstein being responsible for the development of general relativity as a whole.

However, submission dates don’t tell the whole story.

Corry, Renn, & Stachel resolved the question of priority #OTD in 1997. They uncovered a previously unknown printer's proof of Hilbert's draft. It was missing two key elements which Hilbert did not incorporate until after @AlbertEinstein's paper appeared!
https://science.sciencemag.org/content/278/5341/1270

Their paper resolving the dispute appeared 82 years to the day after Hilbert wrote to Einstein, inviting him to attend a lecture in Göttingen. Hilbert promised to present "my axiomatic solution of your great problem," a solution which turned out to be almost but not quite right.

The version of Hilbert’s paper that appeared in print acknowledged Einstein’s priority: “The differential equations of gravitation that result are, as it seems to me, in agreement with the magnificent theory of general relativity established by Einstein in his later papers.”

However, the back-and-forth between Einstein and Hilbert in November 1915 and the preceding months probably did as much as anything to drive Einstein to the final, correct form of his theory.

Sorry, I am contractually obligated to repost this picture from the 100th anniversary of general relativity in 2015.

Unbelievable how for that one day we all suddenly had Einstein hair and now we act like it never happened.