Princess Michael of Kent, a member of The Sovereign Order of the Knights of Malta, was present in Rome for the state funeral of Fra Andrew Bertie, 78, the Briton who headed the knights until his death earlier this month.
Giorgio Napolitano, the Italian president, also attended the ceremony at the organisation's headquarters on the Aventine Hill.
The order, which has 12,500 members, was founded in the 11th century to protect the Holy Land, and was a rival to the equally powerful and secretive Knights Templar.
In the Middle Ages it became fabulously wealthy, owning more than 140 estates in the Holy Land and around 19,000 manors in Europe.
Its membership was drawn exclusively from Europe's aristocracy, which led conspiracy theorists to accuse it of being part of the "Illuminati", a cabal of nobles bent on controlling the world.
But today, the order has 80,000 volunteers working on charitable projects. Winfried Henckel von Donnersmarck, a member of the Sovereign Council, said the order spends £500 million a year helping the world's poor.
"The only mystery here is the one of history. Any organisation with a thousand years behind it is going to have mysteries," he said.
Albrecht von Boeselager, the Grand Hospitaller, said the conspiracy theories hurt the order's work.
"We have been accused of being part of a 'New Crusade', and of sending mercenaries to fight in Iraq. This is not true and it endangers our helpers in Muslim countries," he said.
+++++++++++++++++++++++++++++++++++++++++++++++++++
No responsibility or liability shall attach itself to either myself or to the blogspot ‘Clerical Whispers’ for any or all of the articles placed here.
The placing of an article hereupon does not necessarily imply that I agree or accept the contents of the article as being necessarily factual in theology, dogma or otherwise.
Sotto Voce