In April 2014 I received a letter from the University of Tehran, inviting me to deliver the keynote address to the first Iranian Shakespeare Congress.

Instantly, I decided to go. I had dreamed of visiting Iran for a very long time. Many years ago, when I was a student at Cambridge, I came across a book of pictures of Achaemenid art, the art of the age of Cyrus and Darius and Xerxes. Struck by the elegance, sophistication, and strangeness of what I saw, I took the train to London and in the British Museum stood staring in wonder at fluted, horn-shaped drinking vessels, griffin-headed bracelets, a tiny gold chariot drawn by four exquisite gold horses, and other implausible survivals from the vanished Persian world.

The culture that produced the objects on display at once tantalized and eluded me. A Cambridge friend recommended that I read an old travelogue about Persia. (I had completely forgotten the name and author of this marvelous book, forgotten even that I had read it, until the great travel writer Colin Thubron very recently commended it to me: Robert Byron’s The Road to Oxiana, published in 1937.) Byron’s sharp-eyed, richly evocative descriptions of Islamic as well as ancient sites in Iran filled me with a longing to see with my own eyes the land where such a complex civilization had flourished.

In the mid-1960s, this desire of mine could have been easily satisfied. Some fellow students invited me to do what many others had been doing on summer vacations: pooling funds to buy a used VW bus and driving across Persia and Afghanistan and then, skirting the tribal territories, descending through the Khyber Pass into Pakistan and on to India. But for one reason or another, I decided to put it off—after all, I told myself, there would always be another occasion.

By the time the letter arrived inviting me to Tehran, it was difficult fully to conjure up the old dream. I knew from Iranian acquaintances that, notwithstanding some highly sophisticated and justly praised films—many of them shown only abroad—censorship of all media in Iran is rampant and draconian. Spies, some self-appointed and others professional, sit in on lectures and in classrooms, making sure that nothing is said that violates the official line.

Support for basic civil liberties, advocating women’s rights or the rights of gays and lesbians, an interest in free expression, and the most tempered and moderate skepticism about the tenets of religious orthodoxy are enough to trigger denunciations and arouse the ire of the authorities. Iranian exiles have detailed entirely credible horror stories of their treatment—pressure, intimidation, imprisonment, and in some cases torture—at the hands of the Islamic Republic. A small number of aid organizations, such as the Scholars at Risk Network and the Scholar…