Reality Check: What's in document Pope gave as gift to Trump?
In the Vatican early on 24 May, President Trump and Pope Francis met for the first time.
To mark the occasion the pair exchanged gifts, and President Trump was given a copy of the pontiff's writings on the environment.
Mr Trump received Pope Francis's seminal, 183-page encyclical letter (a Papal document) - published in June 2015 - on the subject of climate change.
"Well, I'll be reading them", Mr Trump said.
Reality Check has been looking into the Encyclical letter to find out what's inside.
What will Mr Trump read?
"The earth, our home, is beginning to look more and more like an immense pile of filth," wrote Pope Francis in the Encyclical 'Laudato Si'.
The letter is a striking message of warning for the world to recognise the scientific consensus about the warming of the planet and blames humanity for rising temperatures:
"Climate change is a global problem with grave implications: environmental, social, economic, political and for the distribution of goods. It represents one of the principal challenges facing humanity in our day."
He calls on those with the economic and political resources to take proactive measures to combat climate change and criticised those who "seem mostly to be concerned with masking the problems or concealing their symptoms." He goes on to urge political leaders to develop policies to ensure "the emission of carbon dioxide and other highly polluting gases can be drastically reduced."
Following the release of the letter, Pope Francis continued to make climate change a core issue of his papacy. Ahead of the Paris climate change summit in November 2015, the Pope told journalists that it was "now or never…Every year the problems are getting worse."
How does this compare to President Trump's views on climate change?
"Global warming hoaxsters".
Before his presidency, Trump expressed pride at his property empire's "great" environmental record which he said "everybody would love" according to the Washington Post in 2011. In the White House, the president has vowed to promote clean air and clean water.
But while the Pope has warned world leaders about the severe threat posed by climate change, Mr Trump has called it a "hoax".
On Twitter in November 2012, the businessman blamed China, it seemed, for inventing global warming.
"The concept of global warming was created by and for the Chinese in order to make U.S. manufacturing non-competitive."
In January 2014 another tweet read "Any and all weather events are used by the GLOBAL WARMING HOAXSTERS to justify higher taxes to save our planet! They don't believe it $$$$!"
On the campaign trail, Mr Trump repeated this view. "I am not a great believer in man-made climate change", he told the Washington Post in March 2016.
After winning the election, Mr Trump has appeared to temper those views, and he told the New York Times he thought there was "some connectivity" between human activity and climate change and that he has an open mind on the subject.
In March, Mr Trump signed an executive order that aims to review President Obama's signature plan to reduce carbon emissions and seeks to remove regulations which the president said holds back domestic energy production.
Last year, Mr Trump promised to "cancel" the landmark Paris climate deal that aimed to reduce global carbon emissions, signed by President Obama.
That decision has been put on hold until after the G7 meeting on 26 May, says the White House. Whether the US pulls out or not could send the biggest signal yet on how the Trump administration views climate change.