Originally Posted by KittyAtlanta
I'm not sure, but I believe royalty of any religious persuasion can wear (and are invited to wear) white for a papal audience, as the Pope is the CP of the Church.
If this is incorrect, please direct accordingly.
Privilege du blanc (privilege of the white) is normally reserved only for female Catholic Monarchs and wives of Catholic Monarchs. Everyone else is supposed to wear black. Queen Elizabeth has always done so during her meetings with the Pope (of the time).
There have been exceptions to this rule, however. Raisa Gorbachyova wore red to meet the Pope. On the other hand, Cherie Blair (wife of the former British Prime Minister) wore white - despite not being the Monarch's or indeed the Head of State's spouse. That caused quite a controversy.