I read in Wiki they were together at the Solvay Conderence. There is also a note from 1926 letter to Paul Ehrenfest, Albert Einstein wrote of a Dirac paper, "I am toiling over Dirac. This balancing on the dizzying path between genius and madness is awful." In another letter concerning the Compton effect he wrote, "I don't understand the details of Dirac at all."
Dirac used special relativity in 1926 as part of the Dirac Equation.
I am scratching my head on the comment from the architect of general relativity arguably one of the crown jewels of human achivement. On the other hand the EPR paper requires deep insight into quantum mechanics to be able to predict the behavior of what entanglement would do well ahead of anyone else. Of course there were two other's who contributed along with Einstein but I rather imagine Einstein understood quantum mechanics. I was wondering if other than what I found above there is more to read?