In a wide-ranging interview on Vox’s The Ezra Klein Show podcast, Zuckerberg discussed election interference, the handling of user data and privacy, the proliferation of fake news, and what to do when your company — with more than 2 billion users — reaches a size and scale where the consequences for failure have a massive impact. Zuckerberg also hit back against Cook’s recent comments.

This isn’t the first time Facebook and Apple – two of the biggest tech companies Silicon Valley – have squared off. Here’s a short history of the spat:

Tim Cook on Facebook’s recent privacy scandal.

Last week, Cook was interviewed on MSNBC by Recode’s Kara Swisher and MSNBC’s Chris Hayes, where he delivered frank words about user privacy following the Cambridge Analytica privacy scandal. (The full interview airs on April 6.) When Swisher asked Cook what he would do if he were Zuckerberg — alluding to the recent issues of user privacy — Cook responded, “I wouldn’t be in this situation.”

He further stated that Apple’s business model was to sell products to consumers and not selling user data to advertisers.

“If our customer was our product, we could make a ton of money,” Cook stated, reiterating late Apple CEO Steve Job’s feelings on privacy. “We’ve elected not to do that.”

Mark Zuckerberg responds to Cook.

When Klein brought up this comment on Facebook and Apple’s differing business models, Zuckerberg pushed back.

“You know, I find that argument, that if you’re not paying that somehow we can’t care about you, to be extremely glib,” he told Klein. “And not at all aligned with the truth. The reality here is that if you want to build a service that helps connect everyone in the world, then there are a lot of people who can’t afford to pay. And therefore, as with a lot of media, having an advertising-supported model is the only rational model that can support building this service to reach people.”

Zuckerberg argued that Facebook is focused on serving its users.

A history of minor tension.

“Relations between Facebook and Apple are a bit like those between the United States and China,” The New York Times’s Nick Wingfield wrote in a blog in 2012. “The two companies, great powers in their own right, are neither friends, nor outright hostile toward each other.”

Apple is the ninth largest company in the world, with revenues of $215 billion and a $754 billion market value. Facebook ranks No. 98 with $27 billion in revenue and a $410 billion market value.

The two tech giants are different enough in what they provide users: Apple deals primarily in hardware, operating systems, and distributing music and other media. Facebook is, obviously, social media — providing a platform for users to connect with friends and share their lives (and their data). (The two, however, are now both in the original content development game, so there will be some competition.)

The late Jobs also at one time applauded Zuckerberg “for wanting to build a lasting company,” according to the Times. Zuckerberg has also professed admiration for Jobs. (And the Atlantic did a comparison of how the two of them have built their companies.)

That doesn’t mean that there haven’t been scuffles between the two, especially when it comes to issues of integrating Facebook with the iPhone. In 2017, the two hit a snag over Facebook’s subscription tool that would encourage users to subscribe to media organizations. Apple wanted to take a cut of the “in app” subscription profits, while Facebook wanted the revenue to go directly to publishers, according to Recode.