Saluted by swiss guards, ushered through room after room filled with stunning renaissance frescoes and then, finally, offered a seat in front of the Pope.  

Even for the most seasoned political leaders, the experience of a papal audience can be a humbling experience. It will be no different for President Donald Trump who today set off on his first foreign trip abroad which will include an audience with Pope Francis inside the Vatican’s apostolic palace next Wednesday.  

The Holy See’s highly ritualised protocol for state visits is unlike any other in modern diplomacy. It is not, however, tradition for the sake of it: there is a clear purpose behind the process...