President Obama called himself a "great admirer" of Pope Francis as he sat down at the Vatican on Thursday with the pontiff he considers a kindred spirit on issues of economic equality.
Obama arrived at the Vatican amid all the pomp and tradition of the Catholic Church.
The United States flag was erected outside the Apostolic Palace in recognition of Obama's visit.
Obama was greeted by a line of Vatican officials.
The president then made his way to greet the pope after a long, slow procession through the hallways of the Apostolic Palace led by colorful Swiss Guards and accompanied by ceremonial attendants.
Obama bowed as he shook hands with the pontiff in the Small Throne Room, before the two sat down at a wooden table in the Papal Library.
"It is a great honor. I'm a great admirer," a broadly grinning Obama said. "Thank you so much for receiving me."
Obama presented the pope with a seed chest filled with fruit and vegetable seeds used in the White House Garden, in honor of the pope's announcement earlier this year that he's opening the gardens of the papal summer residence to the public.
After greeting each other in front of reporters, the pair met in private for nearly an hour.
While it's unlikely the pair talked about politics or their deep differences on abortion and contraception, the meeting was scheduled for just a half-hour but lasted for 52 minutes.