(CNN) For world leaders, meeting the Pope might feel something like being sent to the principal's office. They've all earned a few demerits, after all, and popes are known to have almost impossibly high moral standards. Even Francis, who has made mercy and forgiveness his mantra, can scold with the best of them.

So if President Donald Trump, who has famously feuded with the Pope, had sweated like a schoolboy on Wednesday morning, it would have been understandable.

After months of tweeting and talking past one another , the brash businessman was led through the Apostolic Palace to the Pope's large wooden desk.

There, the President sat on one side, his hands deferentially placed on his lap, while cameras clicked and flashed. Francis, dressed in his habitual white, leaned forward on his desk, as if eager to get the conversation started.

After a few minutes the journalists were shooed away, and the men were left alone. At long last, liberal Catholics might have thought, the holy haranguing would commence.

But that's not this Pope's style. He may be quick to criticize actions, but rarely, if ever, savages someone personally, even if he sharply disagrees with them.

"He hates direct confrontation, and always avoids it," said Austen Ivereigh, author of a well-regarded biography of Francis . "He doesn't believe in humiliating or criticizing people directly."

Indeed, days before meeting Trump, Francis pledged to keep an open mind about the mercurial American President.

"I never make a judgment of a person without listening to them," the Pope told reporters . "I believe that I should not do this. In our talk things will come out, I will say what I think, he will say what he thinks, but I never, ever, wanted to make a judgment without hearing the person."

Neither the White House nor Vatican will likely ever reveal exactly what Trump and the Pope told each other during their private, 30-minute meeting.

In a vague statement, the Vatican said the "cordial discussions" between the Pope and Trump, as well as American and Catholic diplomats, touched on everything from healthcare and education to assistance to immigrants and the "promotion of peace," particularly in the Middle East, from which the President had just traveled.

Whatever Trump and Francis discussed, when photojournalists were allowed back into the Pope's private study, it seemed as if both men had relaxed a bit. Francis, whose Resting Pope Face can seem a bit stern, even smiled a little as the two men exchanged gifts.

Pope Francis exchanges gifts with President Donald Trump during a private audience at the Vatican.

Trump gave the Pope a first-edition set of books by the Rev. Martin Luther King, recalling the Pope's speech to Congress in 2015 in which he quoted the revered civil rights leader. Francis, in return, gave the President a medal of an olive tree, which the pontiff said symbolizes peace.

"We can use peace," Trump said.

Francis also gave the President some homework, or summer reading, if you will: Copies of his three major writings as Pope.

The first, an apostolic exhortation called "The Joy of the Gospel," may take Trump by surprise. The 50,000-word work, in addition to exhorting the Catholic Church to wake from a spiritual slumber, launches a fierce attack on modern capitalism, blasting the "idolatry of money" and calling trickle-down economics "crude and naive."

"The culture of prosperity deadens us," Francis writes in a signature passage. "We are thrilled if the market offers us something new to purchase; and in the meantime all those lives stunted for lack of opportunity seem a mere spectacle; they fail to move us."

The Pope's second written gift to Trump is no easy read, either. In " Laudato Si," Francis calls for a revolution to halt climate change (which the President has called a Chinese hoax) before the Earth devolves into an "immense pile of filth."

"What kind of world do we want to leave to those who come after us, to children who are now growing up?" Francis asks.

on Wednesday, but that Trump hasn't made a final decision about the agreement. The question is particularly poignant as the United States considers reneging on the Paris Climate Agreement, which 147 countries have already ratified. US Secretary of State Rex Tillerson told reporters that his Catholic counterpart, Cardinal Pietro Parolin, raised the subject of climate change on Wednesday, but that Trump hasn't made a final decision about the agreement.

In any case, the Pope's encyclical on the environment calls for more than climate accords. He urges people to put down their smart phones, turn off their televisions and cultivate real relationships.

"When media and the digital world become omnipresent, their influence can stop people from learning how to live wisely, to think deeply and to love generously," Francis wrote, sounding very much like a foil to the Tweeter in Chief.

Finally, Francis gave Trump a copy of "Amoris Laetitia," his book about the challenges facing modern families, and how the church should minister to them.

Much of "Amoris" will probably be too inside-Catholic-baseball for Trump, a self-professed Presbyterian. But there are some lyrical passages on family life that read almost like a novel. ("Let us cross the threshold of this tranquil home, with its family sitting around the festive table ...")

For what it's worth, Trump seemed appreciative of the Pope's literary gifts on Wednesday.

"Well, I'll be reading them," he told the Francis with a smile.

The President says he likes to read , but often gets interrupted by emergency phone calls. Then again, he has a long flight home from Europe on Saturday.

Who knows, maybe he'll settle down on Air Force One and crack open his signed copy of "Laudato Si." After all, Trump did tell Francis, as he bade the Pope farewell, "Thank you. I won't forget what you said."