Royals European Royal Families 5 Future European Monarchs Pose for Epic Photo at Prince Christian of Denmark's 18th Birthday Gala The next generation was all smiles in their evening finery (including tiaras!) at Christiansborg Palace By Janine Henni Janine Henni Janine Henni is a Royals Staff Writer for PEOPLE Digital, covering modern monarchies and the world's most famous families. Like Queen Elizabeth, she loves horses and a great tiara moment. People Editorial Guidelines Published on October 16, 2023 11:01AM EDT Close Princess Estelle of Sweden, Princess Ingrid Alexandra of Norway, Prince Christian of Denmark, Princess Catharina-Amalia of the Netherlands and Princess Elisabeth of Belgium on Oct. 15, 2023. Photo: Keld Navntoft, Kongehuset Prince Christian of Denmark’s glamorous birthday bash doubled as a mini royal reunion. Crown Prince Frederik and Crown Princess Mary’s eldest son turned 18 on Sunday and was fêted with a changing of the guard at Amalienborg Castle in Copenhagen followed by a gala at Christiansborg Palace. Royalty from around the world traveled to Denmark for the evening event, where five future European monarchs posed for a group picture. Prince Christian was all smiles beside Princess Estelle of Sweden, 11, Princess Ingrid Alexandra of Norway, 19, Princess Catharina-Amalia of the Netherlands, 19, and Princess Elisabeth of Belgium, 21, in the snap that the Danish Royal House shared to Instagram. Like Prince Christian, the princesses all follow their parents — Crown Princess Victoria of Sweden, Crown Prince Haakon of Norway, King Willem-Alexander of the Netherlands and King Philippe of Belgium — in the line of succession as their first-born children. The birthday gala came with a glamorous dress code, and Prince Christian completed his white tie ensemble with his new Order of the Elephant regalia. The Danish Royal House revealed that Queen Margrethe recently privately awarded her grandson Denmark’s highest honor of chivalry. Meanwhile, Ingrid Alexandra, Catharina-Amalia and Elisabeth sparkled in tiaras and their own honors, while Estelle — still too young for a tiara — sported a sweet bow in her hair. Prince Christian of Denmark's 18th Birthday Celebrated with Royals from Around the World (and Tiaras!) The guest list for the birthday gala also included Crown Prince Haakon and Crown Princess Mette-Marit of Norway, Princess Ingrid Alexandra's parents. Princess Estelle of Sweden similarly attended alongside her parents, Crown Princess Victoria and Prince Daniel. The Scandinavian royal families are extremely close in both their royal duties and their personal connections. It's not rare to see the Swedish, Norwegian and Danish royal families vacationing together or attending significant events like weddings, funerals and christenings. They also often act as godparents to each other's children — in fact, Princess Victoria, Prince Haakon and Princess Mette-Marit are all godparents to Prince Christian! Princess Ingrid Alexandra's 18th birthday gala in June 2022. LISE ASERUD/NTB/AFP via Getty The picture was reminiscent of a similar shot taken at Princess Ingrid Alexandra’s birthday gala in June 2022. Princess Ingrid Alexandra sat in the middle of Princess Estelle, Princess Catharina-Amalia and Princess Elisabeth, with 3-year-old Prince Charles of Luxembourg adorably perched in a chair beside her. Even at his young age, Prince Charles is second in the line of succession to the Luxembourgish throne behind his father, Prince Guillaume, making all five royals destined to rule one day. Another royal gathering earlier this year also called for a group photo. When Crown Prince Hussein of Jordan married Rajwa Alseif in June, the Royal Hashemite Court released an instantly iconic shot from the evening banquet, where Kate Middleton and Prince William posed with the newlyweds and other royalty from around the world, including the Danish, Swedish, Norwegian, Dutch and Belgian royals. Prince Christian of Denmark's 18th birthday gala. MADS CLAUS RASMUSSEN/Ritzau Scanpix/AFP via Getty Meet Denmark's Royals: Your Guide to the Danish Monarchy's Family Tree The Danish Royal Court gave a fun peek into Prince Christian's Sunday night party on social media, revealing that the musical performance was a surprise organized by Queen Margrethe! "The dance floor was set in motion when Benjamin Hav & Familien gave a concert after the gala event 🎶🎸,” courtiers captioned a clip, where Christian danced and clapped beside his family next to the stage. The prince’s 18th birthday was also a major night for his parents Crown Prince Frederik and Princess Mary, plus younger siblings Princess Isabella, 16, and 12-year-old twins Prince Vincent and Princess Josephine. “The concert was Her Majesty the Queen's surprise for all the guests,” the caption continued. The court recapped the magic on Instagram Monday, sharing shots from the dance floor and Prince Christian’s words of thanks for his guests from the stage at the end of the evening. “It has been an absolutely unforgettable evening, and I really appreciate that you all came from far and wide to celebrate me!” the Danish Royal Court quoted him as saying. Can't get enough of PEOPLE's Royals coverage? Sign up for our free Royals newsletter to get the latest updates on Kate Middleton, Meghan Markle and more! Crown Prince Frederik, Prince Christian and Crown Princess Mary at Christian's 18th birthday gala. Shutterstock Prince Christian gave his first official speech earlier that evening, where he shouted out his peers in the crowd and touched on the challenges of starting a new school last year Prince Christian's birthday gala also welcomed representatives from some of Denmark’s youth organizations plus young people “who have distinguished themselves in the world of sport, art and culture.” Extending the guest list, the palace invited around 200 young people from the Danish Commonwealth, allowing each of Denmark’s municipalities, Greenland and the Faroe Islands to invite two 18-year-old guests to the party. “I would like to thank everyone who helped celebrate me. Both you who are here and all of you who have sent greetings and gifts. I will never forget today. But maybe I will remember it as less challenging already tomorrow,” he said in his address, per a translation. “I have to find my way, even if it leads to a familiar place. I have roots in many places in the world and I enjoy traveling. But home will always be here. Because I love my country,” the future king concluded. Queen Margrethe, Prince Christian and Prince Frederik from the balcony of Frederik VIII at Amalienborg Castle in Copenhagen. MADS CLAUS RASMUSSEN/Ritzau Scanpix/AFP via Getty In an interesting twist, Christian’s birthday festivities continue next month. On Nov. 14, the royal will attend a meeting of the Council of State (which is comprised of government ministers) and declare that he wishes to comply with the Danish constitution. “Prince Christian will then be able to be appointed as head of state. Prince Christian will not get a seat in the Council of State until a change of throne has taken place,” the Danish Royal House said of the important step. Over the summer, the Danish Royal House announced that Prince Christian won't take the government funding he is entitled to by law when he turns 18. Instead, he will continue to focus on his studies, and the issue will be revisited when he turns 21 or if there is a change of throne. “His Royal Highness Prince Christian turns 18 on 15 October 2023,” courtiers said in a statement on Instagram, posting the prince’s cypher. “Prince Christian's main priority in the coming year will be the completion of the Prince's upper secondary education. In continuation of this, the Royal Palace will provide information on Prince Christian's further youth and education courses when the time is right.”