Only seven women in the world can wear white to meet the Pope - and Queen Camilla isn’t one of them

King Charles and Queen Camilla are currently in Rome meeting with Pope Leo in their first official meeting with the pontiff since his election.

Their meeting will mark an historic occasion as King Charles becomes the first British monarch to pray with a pope since Henry VIII's break with Rome and the English Reformation nearly 500 years ago.

The occasion marks the culmination of years of bridge-building between the UK and the Vatican after what could be a described as a 'complicated' 500-year-long history which has involved eligious genocide, wars, and even one king being dethroned by Parliament partly over concerns around a Catholic dynasty of monarchs.

And while relations between the British monarchy and the Vatican have certainly thawed since then, some signs still allude to that history in a small way.

Among them is the outfit that Queen Camilla wore during the official visit.

Camilla donned black and a mantilla for her meeting with Pope Leo (Franco Origlia/Getty Images)

Camilla wore black for her meetings with Pope Leo, like many other royal women who have met the pope.

This is because Camilla does not have permission to wear white when meeting the pope; only seven women in the world have that privilege.

Protocol means that most women meeting the pope should wear black, with no cleavage, as well a mantilla, which is a kind of headscarf.

Permission to wear white is known as 'il privilegio del bianco' in Italian or 'le privilège du blanc' in French, literally meaning 'the privilege of white'.

The seven women who have the right are Princess Charlene of Monaco, Queen Mathilde of Belgium, Queen Letizia of Spain, Grand Duchess Maria Teresa of Luxembourg, and Princess Marina of Naples.

There are also two Queens whose husbands don't reign anymore who retain the privilege, and they're Queen Sofia of Spain and Queen Paola of Belgium.

Pope Leo was elected following the death of Pope Francis (ALBERTO PIZZOLI/AFP via Getty Images)

Royal women who have 'il privilegio del bianco' are themselves Catholic.

And given the long history between Britain and the Vatican, the King and Queen are not Catholic, so Camilla does not have that privilege.

The visit will see Charles pray with Pope Leo, with Charles of course also being the head of a church himself as the British monarch is the head of the Church of England.

While Charles and Camilla also visited Pope Francis, their visit represents an important moment between Britain and the Vatican.

They will also celebrate the Papal Jubilee, which occurs once every 25 years and will begin with their royal visit.