Ramanujan’s Letter to Hardy
In January 1913, British Mathematician, GH Hardy, received mail a package from an unknown clerk from Madras. The package had a cover letter signed by S. Ramanujan and contained nine pages of technical papers from a bunch of areas in mathematics.
At first, Hardy thought it was a fraud, then he came to recognize the brilliance the papers. After exchanging a few more emails with Ramanujan, he invited him to study at Cambridge with him and the rest is history.