“You should’ve seen some of the mail I got,” Schwarzman said. “I was accused by people of being a Nazi. I mean I’m Jewish. I got hundreds of these things.”

Speaking for the first time since President Donald Trump’s two business councils dissolved, Schwarzman, who headed one of those groups, said he and his fellow CEOs were under enormous pressure from their shareholders to cut their ties to Trump during a Tuesday CNBC and Institutional Investor Delivering Alpha conference.

That was after the commander-in-chief said “both sides” were responsible for the violence in Charlottesville that culminated when a counter-protester at a white supremacist rally was fatally mowed down by a car in mid-August. While only a few CEOs from Trump’s Manufacturing Council and Strategy and Policy Forum resigned from the advisory bodies at first, more CEOs continued toward the exit, and the two groups eventually crumbled just days later after Trump reasserted that he meant what he said.

Despite disagreeing with Trump’s decision to pull out of the Paris Agreement, however, most CEOs on those two advisory boards decided to stay. They argued that a position on the council allowed them to help shape the President’s views. So, what changed between then and August?

While part of the reason CEOs resigned was purely in protest over what appeared to be Trump’s sympathy toward neo-Nazis, CEOs of those groups were also facing intense criticism from their shareholders, Schwarzman said during Tuesday.

“There were shareholders that were unhappy with (CEOs’) affiliation,” Schwarzman said. “It was too much for CEOs of public companies to have so many constituents attacking you.”

Virtually no one, he said, “could deal with the pressure from their constituents.”

The CEO of Blackstone noted that it reminded him of the 1960s, when the Civil Rights movement was in its prime.

“It was pretty clear that the country was going out of control,” he said, saying that the CEOs from the two advisory groups gathered together and jointly decided to dissolve. They also informed the White House of their intentions.

“Then the President stepped ahead of that with his tweet,” Schwarzman said, referring to Trump’s tweet in which he announced the end of both the Manufacturing Council and the Strategy and Policy Forum.

“Rather than putting pressure on the businesspeople of the Manufacturing Council & Strategy & Policy Forum, I am ending both. Thank you all!” the tweet read.

Although Schwarzman didn’t explicitly say why he thought Trump pre-empted either business group’s announcement with the tweet, the CEO did say: “Well this is the political world. I don’t control the political world… We made the decision, we communicated that to the White House, and that is what ended up happening.”

Schwarzman noted that he was still in contact with the President.

The CEO’s talk came just after Treasury Secretary Steven Mnuchin spoke about the dissolution of the two business advisory groups, saying that it was a “mistake.”