Dutch King Willem-Alexander was sworn in at a solemn ceremony on Tuesday as the cream of Europe's monarchs-in-waiting gazed on, raising the question of who would be next.
Willem-Alexander, 46, was enthroned as the Netherlands' first king in more than 120 years in Amsterdam's Nieuwe Kerk church in front of 2,000 guests, among them several crown princes and princesses.
Protocol dictates that reigning sovereigns are not invited so as not to overshadow the new king's presence.
Foremost among the blue-bloods was Britain's Prince Charles and his wife Camilla, radiant in a powder-blue dress, who watched attentively from a front-row seat as the ceremony unfolded.
"No doubt he watched the ceremony today with longing in his heart," said royal expert Jeroen Snel, presenter of the Dutch weekly royalty show Blauw Bloed (Blue Blood).
"You must remember that he was also present when queen Beatrix was enthroned in 1980 and it must be a bit of a bitter pill for him to swallow," Snel told AFP.
Unlike Dutch queen Beatrix, 75, who abdicated after 33 years on the throne to hand over to what she called "a new generation", the British monarch has made it clear that she has no intention of stepping down.
Queen Elizabeth, 87, is entering her 61st year on the throne and some polls have shown the British public are more inclined to see Charles' oldest son William and his wife Kate take over the reins.
Spain's Crown Prince Felipe, 45, was also present amid growing calls for his father King Juan Carlos, 75, to abdicate after a number of recent scandals.
The king won wide respect for helping guide Spain through a political transition after the death of dictator Francisco Franco in 1975 but a recent poll showed 53 percent disapprove of the king.
But his popularity plunged after he last year went on a luxurious hunting trip to Botswana while many Spaniards struggled with unemployment and the recession.
Carlos' youngest daughter was also recently named a suspect in an embezzlement case centred on her husband Inaki Urdangarin.
Also dogged by scandal is Swedish King Carl Gustav XVI, who has been on the throne almost 40 years and finds himself regularly lampooned in the Swedish press.
His hugely popular 35-year-old daughter Crown Princess Victoria, dressed in a stunning beige pearl dress and stylish hat, is due to succeed her father.
But the person stealing the show on Tuesday was none other than King Willem-Alexander and Queen Maxima's eldest daughter, Catharina-Amalia, 9, next in line to the throne.
Dressed in a matching blue outfits, the new Princess of Orange and her two sisters, Alexia, 7, and Ariane, 5, sat next to their grandmother, now Princess Beatrix, during the ceremony.
When, as the likely future queen of the Netherlands, she was thanked for her presence at the investiture, Catharina-Amalia gave a royal nod, much to the amusement of the other guests present in the church.