The potential political consequences are hugely important. Mehdi Khalaji points to Ayatollah Khomeini’s ailments and Mohammad Reza Shah’s cancer, both of which were kept secret for a long time.

“Ayatollah Khomeini had a stroke in 1986 and became comatose,” says Khalaji. From 1986 to 1989, a number of crucial historical events took place, from the conclusion of the war between Iran and Iraq to the removal of Ayatollah Montazeri as heir apparent to Khomeini, to the fatwa against novelist Salman Rushdie and the revision of the constitution. But later “we realized that in 1986 Khomeini was actually on death’s doorstep” and his ability to deal with these developments afterward was extremely limited.

In the case of the Shah, Khalaji points out, even Queen Farah did not know about his cancer until a few months before leaving Iran. “The Shah’s cancer affected his decisions; it made him a passive decision-maker,” Khalaji says. “If the Shah did not have cancer, major events could have gone in another direction.”