King Willem-Alexander and Queen Máxima, King Philippe and Princess Mathilde (then still the Duke and Duchess of Brabant), King Felipe and Queen Letizia (then still the Prince and Princess of Asturias) and the Prince of Monaco: none of them did attend the wedding of Princess Madeleine and Mr Christopher O'Neill.
No one else represented the Netherlands, Belgium or Spain. That Belgium was absent, was remarkable since King Philippe and his siblings are grandchildren to a Princess of Sweden. The Princess of Monaco did attend all alone, which is unlikely now: maybe she prefers to stay with Prince Jacques and Princess Gabriella. The United Kingdom did send the Earl and Countess of Wessex, but they most likely will attend the Queen's Birthday Parade in London.
So my prediction:
Denmark:
The Crown Prince and -Princess
Prince Joachim and Princess Marie
Norway
The Crown Prince and -Princess
Princess Märtha Louise and Mr Ari Behn
The United Kingdom
- no royal representation
The Netherlands
- no royal representation
Belgium
- no royal representation
Luxembourg
- The Hereditary Grand Duke and -Duchess
Spain
- no royal representation
Monaco
- no princely representation
Liechtenstein
- no princely representation
The former Greek royal family
- Prince Pavlos and Princess Marie-Chantal
- Prince Nikolaos and Princess Tatiana
The former German royal families
- Princess Benedikte of Denmark, Princess zu Sayn-Wittgenstein-Berleburg
- Prince Gustav zu Sayn-Wittgenstein-Berleburg and Ms Carina Axelsson
- Count Jefferson-Friedrich and Countess Alexandra von Pfeil und Klein-Ellguth, born Princess zu Sayn-Wittgenstein-Berleburg
- Mr Alexander and Mrs Nathalie Johannsmann, born Princess zu Sayn-Wittgenstein-Berleburg
- the Hereditary Prince and -Princess von Sachsen-Coburg und Gotha
- Prince Leopold and Princess Ursula von Bayern