Elon Musk is going to 'war' with Apple. Here's a look at the billionaire's years-long beef with the tech giant.

The billionaire accused Apple of monopolizing the market and opposing free speech in a series of tweets.

"Apple has mostly stopped advertising on Twitter," Musk tweeted on Monday. "Do they hate free speech in America?"

In a series of tweets, Musk accused Apple of being politically biased, called for Apple to publish all actions it has taken toward censorship, and asked his followers for support in his fight against the largest tech company in the world.

The Tesla CEO and "Chief Twit" later added that Apple had "threatened" to take Twitter off its App Store and "won't tell us why."

A spokesperson for Apple did not respond to a request for comment from Insider ahead of publication.

According to Tim Higgins' book "Power Play: Tesla, Elon Musk, and the Bet of the Century," Tim Cook had suggested that Apple acquire Tesla in 2016.

At the time, Musk reportedly said he wanted to be CEO and Cook allegedly agreed, until Musk clarified that he wanted to be CEO of Apple — not just Tesla.

According to the book, which cited a source who had heard Musk's retelling of the exchange, Cook said "Fuck you" before hanging up the phone on Musk.

Both Musk and Apple have denied the reports, saying the two CEOs have never spoken.

"There was a point where I requested to meet with Cook to talk about Apple buying Tesla," Musk said on Twitter when the book came out last year. "There were no conditions of acquisition proposed whatsoever. He refused to meet. Tesla was worth about 6% of today's value."

In a 2018 interview with Recode's Kara Swisher, Musk said Apple's products have grown stale.

"There's not many products you can buy that really make you happier," he said. "I still think, obviously, that Apple makes great phones. ... I still use an iPhone and everything. But Apple used to really bring out products that would blow people's minds, you know? And still make great products, but there's less of that."

Musk compared Apple to Tesla, saying Tesla planned to avoid Apple's pitfalls when it comes to consumer interest.

"I don't think people are necessarily running to the store for the iPhone 11," Musk said. "But I think with Tesla, we really want to make products that people just love, that are heart-stopping."

Phil Schiller, the senior Apple executive who runs the company's App Store, deactivated his Twitter account in November, shortly after Musk reinstated Donald Trump's account, per Bloomberg.

Schiller had hundreds of thousands of followers on the site and had formerly served as the company's head of marketing, The Independent reported. His decision to delete his account spawned headlines and raised eyebrows across the industry.

"Did you know Apple puts a secret 30% tax on everything you buy through the App Store?" Musk tweeted on Monday.

It was one of many times the billionaire has criticized Apple for its App Store fees.

In 2021, he called the fees a "de facto global tax on the Internet," and earlier this month, he tagged the Department of Justice's antitrust division in a criticism of the fees.

Now that he owns Twitter, Apple's fees could have an impact on Musk's business and his plans to generate revenue by charging users $8 per month for verification on the social media site.

The tech company controls app distribution for the iPhone and iPad, and takes between 15% and 30% of most in-app purchases made on iOS apps. The company typically requires that developers use in-app payment systems, though it has slightly softened that requirement for certain apps like Netflix and Spotify.

Cook has yet to respond to Musk on Twitter, even though the Tesla CEO called out the Apple CEO directly on the social media site.

"What's going on here @tim_cook?" Musk tweeted on Monday, after saying Apple had stopped spending ad money on Twitter.

In the first quarter of this year, Apple was the top advertiser on Twitter, accounting for 4% of the social media company's revenue, according to The Washington Post.

Up until Musk's takeover, Twitter and Apple appeared to enjoy a symbiotic relationship. Apple has frequently used the site for product announcements, and Apple even integrated tweets in its iOS operating system in 2011.

But Musk's recent actions might sour the relationship between the two companies. Ultimately Apple could decide to oust Twitter from its App Store over content moderation concerns.

In a op-ed with The New York Times, Yoel Roth, Twitter's former head of trust and safety, said that "the calls from the app review teams had already begun" when Musk's roll out of paid verification badges led to chaos, with users impersonating public figures and major companies.

The billionaire has been known to start his fair share of feuds on Twitter, and he's never appeared hesitant to speak his mind.

Most recently, Musk has publicly argued with Rep. Alexandria Ocasio-Cortez and Stephen King on Twitter.

Meanwhile, Musk has personally called up CEOs of companies that have pulled ads from Twitter to complain, Financial Times reported on Sunday.

While Apple's business could be key to Twitter's success, Musk has shown he isn't afraid to ruffle a few feathers.