The conference in the heart of Silicon Valley had actually been held March 2 and 3, with a dozen sessions, including ones dedicated to questions like “Are recent developments in American politics unprecedented, or is Trump merely populism revisited?” and “What can we learn from past attempts to learn from the past?”

Mr. Ferguson is no stranger to controversy. But on Thursday he acknowledged that the conference needed more diversity.

“Everybody was keenly aware that it was too white and too male,” he said. The problem was “explicitly discussed” ahead of the event, Mr. Ferguson said. He also said that women had been invited, but all, except one, were unable to attend.

Three female historians who had been invited confirmed to The New York Times that they had declined because of other obligations. The only woman at the event, Mary Sarotte, who headed a single panel, did not respond to a request for comment.