Inside the divided Fox News bunker, many seasoned executives are wondering if they are living in an alternate universe. As shocking as the Roger Ailes fiasco may have been, and as surprising as Megyn Kelly’s departure went down, Bill O’Reilly’s sudden ouster has absolutely shaken the newsroom, according to multiple insiders. (Ailes has fervently denied all accusations.) Executives spent a contentious Wednesday in various closed-door meetings as they finalized the fate of the network’s biggest star, who was forced out amid news of sexual-harassment allegations and settlements of those allegations.

The reactions to the news of O’Reilly’s departure were decidedly mixed in the newsroom. Some staffers cried. Others were elated. The move also laid bare divisions between the Murdoch sons, Lachlan and James, and their father, who were on opposite sides of the argument about whether to retain the anchor, according to a person close to the family. Eventually, though, Rupert Murdoch agreed with his sons about the need to remove O’Reilly, this person added. And the day was filled with an ominous tension as the elder Murdoch, the network’s C.E.O., moved from one closed-door meeting to another to inform on-air talent of their new jobs.

While his fate may have seemed sealed earlier in the week, O’Reilly’s attorneys did not get the official word of his departure until this morning, according to two people familiar with the matter. And O’Reilly, who was enjoying a vacation in Italy, only formally learned of his demise en route to the airport. (In a statement, O’Reilly noted, “It is tremendously disheartening that we part ways due to completely unfounded claims. But that is the unfortunate reality many of us in the public eye must live with today.”) Within Fox News, it remains unclear how much O’Reilly may receive in severance, but some sources speculated that the figure could be in the ballpark of the $40 million that Ailes received.

The move to dethrone O’Reilly, once unimaginable, crystallized over the past week, as advertisers continued to flee his show, more women came forward, and, perhaps most important, Fox News management came to realize that there was no way to stem the possibility that more accusers might surface, anonymously or not, and that O’Reilly would be a liability for the company as long as he stayed on at the network. Tonight, for the first time, O’Reilly’s name will be removed from the show, which will air as simply The Factor. It is, in some ways, an astonishing moment in the history of the network, in particular, and cable news, in general. For while Ailes may have masterminded Fox News’s particular brand of coverage, O’Reilly grew to become synonymous with the network. And in many ways, he carried it on his very back since it launched in 1996.

O’Reilly, after all, was the first Fox News personality to beat CNN, as he did when he overtook Larry King in 2000. The development spurred Ailes to create an ad for him, “The New King of Cable,” that foreshadowed Fox News’s eventual dominance in the space. Today, the network has 13 of the top 15 cable shows, but some wonder how much longer that will last. Within the newsroom, some are simply astonished by what has transpired at Fox News. In less than a year, Fox News has lost its two biggest stars, and saw its mastermind evicted. Now the pressure falls upon Tucker Carlson, who joined the prime time lineup a few months ago, and will now fill O'Reilly’s 8 p.m. slot. The Five, which helped popularize the "leg cam,” will move to 9 p.m.