Global delegates at the Vatican
Read on to see some of the most influential leaders in attendance.
Chancellor Angela Merkel - Germany
Prime Minister Jean-Marc Ayrault - France
Grand Duke Henri - Luxembourg
Vice President Joe Biden - United States
President Robert Mugabe - Zimbabwe
The Vatican did not officially invite any delegations, and said all were welcome to attend.
President Ma Ying-jeou - Taiwan
Prince Richard, the Duke of Gloucester - Great Britain
Pope Francis once called the British "usurpers" of the Falkland Islands.