CNN  — 

Donald Trump and Pope Francis are not the first president and pontiff to tweet. But they are the first to use the social media platform so prolifically, and pointedly.

Francis – or, rather, Vatican staffers – maintain papal Twitter accounts in nine languages, with more than 32 million followers. Trump boasts more than 30 million followers in his personal account and nearly 18 million more in the official @POTUS handle.

All eyes will be watching those accounts in the hours after Trump and Francis meet in Vatican City on Wednesday. (Here’s an in-depth preview of their historic encounter, which will bring together two complex and contrasting personalities.)

The Pope and President are expected to put aside their differences during the meeting, but, as their Twitter history shows, they haven’t always been singing the same tune.

One big caveat: The Pope doesn’t tweet himself; his staffers often choose snippets from his sermons and speeches. So, we should probably resist the urge to read his tweets as 140-character assassinations of Trump, or anyone else.

With that in mind, here’s how things started:

Pretty well, actually. Trump tweeted his congratulations after Francis was elected in 2013.

Just five days later, though, Trump expressed disapproval that – gasp! – Francis had paid his own hotel bill.

By December, Trump had decided that, actually, he kinda liked the Pope. In fact, he saw a certain resemblance between himself and the humble pontiff.

Trump even said Francis would be his top choice to star on “Celebrity Apprentice.”

Just a few months later, though, the lovefest ended. The Pope said anyone who thinks only of building barriers instead of bridges – a clear reference to Trump’s Mexican wall proposal – is “not Christian.”

Trump tweeted out this retort, which he posted on Facebook.

The Pope is a political pawn? Ouch. But if Francis is intimidated, his Twitter handle hasn’t shown it. In March, he echoed his message on bridges and walls.

Francis has also called on world leaders to welcome migrants, who he says are suffering through the worst humanitarian crisis since World War II. Three days after the President signed his first executive order, which would indefinitely bar Syrian refugees, the Pope went Old Testament on Trump.

And days before the Conservative Political Action Conference hosted a panel called “If Heaven has a gate, a wall, and extreme vetting, why can’t America?,” Francis said, essentially: Nope. Nuh-uh. That’s not how heaven works.

But the Pope, as you might have guessed, is a big believer in forgiveness.

And just hours before his meeting with Trump, he seems ready to let bygones be bygones.

What will the Pope and President say after their meeting? Followers of @Pontifex and @RealDonaldTrump may be the first to know.

Bonus tweet: Trump said on Wednesday that it was “the honor of his life” to meet Pope Francis.

VATICAN CITY, VATICAN - MARCH 29:  Pope Francis waves to the faithful as he leaves St. Peter's Square at the the end of Palm Sunday Mass on March 29, 2015 in Vatican City, Vatican. On Palm Sunday Christians celebrate Jesus' arrival into Jerusalem, where he was put to death. It marks the official beginning of Holy Week during which Christians observe the death of Christ before celebrations begin on Easter.  (Photo by Franco Origlia/Getty Images)
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02:01 - Source: CNN