In a rare comment last week, Iran’s 75-year-old supreme leader, Ayatollah Ali Khamenei, told reporters he was going to a hospital for a “routine operation.” Press TV later reported he successfully underwent prostate cancer surgery.

The last time the Iranian public saw images of Khamenei in a hospital was back in 1981. At the time, he was recovering from an assassination attempt by the opposition Mujahedeen-e-Khalq. Khamenei, who was then a senior member of his predecessor Ayatollah Ruhollah Khomeini’s administration, lost his right arm. Soon after that, Khamenei’s images became ubiquitous. He was seen in a military uniform on the front lines chatting with soldiers fighting Iraq during the Iraq–Iran war, which lasted from 1980 to ’88. Another famous image was of then-President Khamenei lambasting the U.S. at the U.N. General Assembly in 1987.

The reason for the latest surgery is far less revolutionary.

The image of the aging Khamenei recuperating in a hospital bed and being kissed by President Hassan Rouhani has led to speculation about janesheen, or succession, by Iran observers and probably by people at the higher echelons of Iranian politics.

The subject of choosing a successor was not publicly discussed until this spring. “May the Almighty protect the leader and prolong his life,” said assembly member Ayatollah Gholam Ali Dori Najaf Abadi in May during a meeting of Assembly of Experts. “But in any case, we have to think about what will be after him.” Few people at the time took note of his statement. After all, Khamenei appeared physically fit and going strong.

But his hospitalization is likely to create concerns that Iran he is ailing more than previously thought.

For years it was rumored that Khamenei had prostate cancer. However, since Iranian politics is rife with rumors, many Iran watchers were skeptical of such reports. It is now clear that reports about his ailing health were more than just rumors.

Thus the question, Who will be his successor? And will a new supreme leader usher in changes to Iran’s foreign policy, nuclear program and relations with the U.S.?