For most of his life, Sam Altman has resembled an accelerating train. He founded a startup as a teenager, achieved middling success — and then jumped to running Silicon Valley’s premier startup accelerator. After that, Altman co-founded OpenAI, whose ChatGPT tool has whipped up a frenzy of excitement about generative AI. Now 38, Altman has become the face of an AI-fueled future, traveling around the world to explain to world leaders and everyone else how the technology he’d helped create would change everything about human existence. He was the most Silicon Valley person alive.

Then, on Friday, he was fired.

Speculation, shock and memes about the sudden shakeup blazed through the tech industry. What happened? The details are still coming out, but Altman and the board had clashed on discussions over how to minimize the possible harms of AI. One thing is already clear: Some of Altman’s relationships within AI had gone off the rails. Usually, when a founder is pushed out, there’s some attempt to make it seem friendly – the founder will “stay on as an adviser” or migrate from CEO to board chair. OpenAI’s remaining leadership, however, made no effort to hide the acrimony. In a statement, they said Altman was “not consistently candid” – essentially accusing him of lying – and said the board “no longer has confidence” in his ability to lead.

The brutality was obvious. “To insiders, it read like an assassination,” said one person who works in AI, who asked for anonymity to avoid damaging relationships.

It was a particularly unceremonious end for Altman, who is usually the person pulling the strings, not the puppet being jerked around. In his two decades in Silicon Valley, Altman solidified a reputation as ambitious, cunning, even Machiavellian. At each stage of his career, he managed to accumulate more influence and force. Altman credits his ability to end up on top to canny strategy, not luck. "A big secret is that you can bend the world to your will a surprising percentage of the time,” he wrote on his blog in 2019. “Most people don’t even try.”Read more: Silicon Valley Boardroom Coup Leads to Ouster of an AI Champion

Altman studied computer science at Stanford University, then dropped out to start Loopt, a social app that showed users their friends’ locations. In 2005, when he was 19, Loopt was accepted to the first-ever cohort at Y Combinator, the now-famous startup accelerator. The first cohort of YC companies, all of them founded by men, went on to become a part of Silicon Valley lore. They included household names like Twitch and Reddit. Loopt was a relative flop, eventually getting acquired for little more than it raised.

But Altman succeeded in a more important way: He had won over Paul Graham, the head of YC, as the incubator is widely known. Graham was impressed by the way the young entrepreneur gravitated toward power and wielded it to his advantage. “You could parachute [Altman] into an island full of cannibals and come back in five years and he’d be the king,” Graham wrote in 2008, when Altman was in his early 20s. A year later, he wrote that Altman was one a few people “with such force of will that they're going to get whatever they want.”

In 2014, Graham anointed Altman as the next head of YC. By that time it had already notched a few successes such as Airbnb, Dropbox, Stripe and Instacart, and running it placed Altman at the center of the startup world. At the time, many venture capitalists scratched their heads. They didn’t know much about this 28-year-old – just that Graham trusted him and called him “fearsomely effective.”

YC founders appreciated Altman’s accessibility and his willingness to go to bat for them. Slava Akhmechet remembered seeking Altman’s help when his company, the database company, RethinkDB, was facing blowback from investors. Though Altman didn’t know the RethinkDB founders that well, he secretly pulled out his phone and “called our investors and pleaded, harangled (sic) and threatened to walk them off the ledge,” Akhmechet wrote in a post on X.

Altman is chatty, energetic, and studiously optimistic about tech. When people meet him, they often comment on his eyes, which stare with an unsettling intensity. But his eyes are metaphorically big as well. At YC, he raised a larger fund to continue investing in YC companies as they grew, and he increased the number of companies in each cohort. In his essays about startups, he espoused a love for bigger scale, bigger dreams. “The most successful founders do not set out to create companies,” he wrote. “They are on a mission to create something closer to a religion, and at some point it turns out that forming a company is the easiest way to do so.”

While at YC, Altman had the resources to indulge in some of his interests outside of tech, like racing cars. He also threw himself into doomsday prepping, telling the New Yorker in 2016 that he and his friends worry about an apocalypse due to “lethal synthetic viruses” or AI gone rogue. “I have guns, gold, potassium iodide, antibiotics, batteries, water, gas masks from the Israel Defense Forces, and a big patch of land in Big Sur I can fly to,” he told the magazine.

That fear of possible AI-related apocalypse motivated Altman to start OpenAI with Elon Musk, Greg Brockman, and Ilya Sutskever in 2015. The organization was initially a non-profit aimed at advancing AI in a way that would benefit humanity and not be dictated by financial gain. For the first few years, things at OpenAI seemed peaceful. But Musk left the company in 2018 after internal turmoil; soon after, OpenAI reorganized itself as a capped for-profit entity. Altman became CEO, then arranged for a $1 billion investment from Microsoft.

Altman’s writings from the same period lean heavily into the idea of going bolder and more ambitious. “It’s useful to focus on adding another zero to whatever you define as your success metric—money, status, impact on the world,” he advised in a blog post titled “How To Be Successful.” He also encouraged startup founders to “have almost too much self-belief” because it’s “immensely powerful.” “The most successful people I know believe in themselves almost to the point of delusion,” he wrote. (“I mostly got what I wanted by ignoring advice,” he told a podcaster this year.)

In the past few years, Altman has invested in companies that are trying to extend human lifespan, make human egg cells from blood cells, and advance nuclear fusion. He also co-founded Worldcoin, a crypto startup that’s trying to scan people’s irises with a silver orb-shaped custom machine as a way to distribute money. (Altman came up with the idea, enlisted a co-founder to run it and isn’t involved in day-to-day operations.)

A basic element of Silicon Valley mythos is the founder who is sent into exile, only to return again for a triumphant second act. Altman’s sudden defenestration from one of tech’s most prominent companies uncharacteristically moves him further away from the center of the action. It’s safe to assume he’s already plotting his return.