I think the point the Palace is trying to make is The Queen Mother, Sophie, Camilla and Catherine are/were all married to Peers and thus were styled as the wives of Peers ("The Duchess of Cornwall, Cambridge, York, etc. The Countess of Wessex"). However, in Camilla's case, she is actually The Princess of Wales, so using their interpretation, she is a princess, not just a duchess, although she chose not to use her senior title after her marriage.
In any case, any woman who marries a Prince of the UK automatically becomes a Princess of the UK with the style and rank of HRH. The only exception to this was in 1937 when George VI issued Letters Patent stating Wallis Simpson would be denied the right to share her husband's royal rank.
If the Palace is trying to say wives do not automatically become Princesses, then why was it necessary to issue letters patent to deny Wallis royal rank as HRH, which was enjoyed as "HRH The Princess Edward", the wife of "HRH The Prince Edward" automatically in law and common practice?
It really isn't clear what they are trying to emphasize, except perhaps their displeasure as Elspeth said, with the statement from Clarence House that people may call Catherine "Princess Catherine" if they wish. That is totally incorrect as she is now a royal duchess as HRH The Duchess of Cambridge.
In any case, any woman who marries a Prince of the UK automatically becomes a Princess of the UK with the style and rank of HRH. The only exception to this was in 1937 when George VI issued Letters Patent stating Wallis Simpson would be denied the right to share her husband's royal rank.
If the Palace is trying to say wives do not automatically become Princesses, then why was it necessary to issue letters patent to deny Wallis royal rank as HRH, which was enjoyed as "HRH The Princess Edward", the wife of "HRH The Prince Edward" automatically in law and common practice?
It really isn't clear what they are trying to emphasize, except perhaps their displeasure as Elspeth said, with the statement from Clarence House that people may call Catherine "Princess Catherine" if they wish. That is totally incorrect as she is now a royal duchess as HRH The Duchess of Cambridge.