The royal couple also met the head of the Catholic church in his papal study – close to the Casa Santa Marta hotel where he lives – rather than the lavish apostolic palace where his audience with Barack Obama took place last week.
And in keeping with the informal nature of the half hour visit, the Queen was not wearing black and did not don a mantilla veil - the usual requirement for women meeting the Pope.
To honour the occasion the Queen gifted the pop with a hamper of royal estate products and framed photos of herself and Philip while the pontiff gave Prince George an orb of lapis lazuli with the Cross of St Edward the Confessor and a copy of the 1679 decree turning King Edward from an English saint into a universal saint.
Her Majesty did not attend the Argentinian religious leader's inauguration last March – and instead sent the Duke of Gloucester to represent her. She does, however have a long history of meeting papal leaders.
The visit with Pope Francis will be her seventh meeting with a head of the Catholic church. Her first was with Pius XII in 1951 when she was still Princess Elizabeth. Ten years later she had an audience with John XXIII and met his successor John Paul II three times – in 1980, 1982 and 2000.
Pope Francis' predecessor Benedict XVI visited the sovereign during his visit to the UK in 2010. Of the seven encounters, five took place in Rome.
This week's trip mark's the Queen's first foreign visit since she went to Australia in 2010. She and Prince Philip will arrive at lunchtime in Rome, where they will spend one day.
The royal couple will begin with a meeting with Giorgio Napolitano, Italy's octogenarian president, before crossing the Tiber for their private, half-hour encounter with the 77-year-old Pope.