Robert Mugabe topped the list of people you'd probably least like to see on your first day at work.
He was seen being pictured by an official who was holding an iPhone with a pink case.
Argentinean president Cristina Fernández de Kirchner was seen in the front row dressed in black, just a day after she lobbied Pope Francis over the Falkland Islands.
They were part of the representatives from 132 countries who attended the inauguration.
Ken Clarke and Baroness Warsi represented the UK along with the Duke of Gloucester.
Robert Mugabe appears to pose for an iPhone photo
Cristina Fernández de Kirchner covers her eyes from the Roman sun
Prince Albert of Monaco showed his respects
Meanwhile, German chancellor Angela Merkel - currently a focus of protest over the Cyprus banking crisis - was also in attendance.
Taiwan's president Ma Ying-Jeou also turned up despite angering Beijing.
Taiwan's President Ma Ying-jeou, left, and his wife Chow Mei-chin