The Swedish court celebrated the 80th birthday of King Carl XVI Gustaf with a ceremony attended by royal families from half of Europe, and from Bangkok too. A Te Deum in the palace chapel, the changing of the guard, a gala dinner in the evening - the script for such events is familiar, but the guest list reveals much more than the protocol.

Carl Gustaf is the longest-reigning monarch in Europe. More than 52 years on the throne, more than half a century in public life. Queen Silvia, who was an ordinary citizen before marrying him, has stayed by his side for 50 full years - a scenario that was a turning point in Swedish history, but would barely register as remarkable in Balkan memory.

At the ceremony were all those who had to be there: Crown Princess Victoria with her husband and children, Prince Carl Philip with Princess Sofia and their four children, Princess Madeleine with three children. The one-year-old Princess Ines drew attention, as did 14-year-old Estelle, who in pale blue looked surprisingly mature and carefully tended to her younger brother Oscar. Princess Margaretha, the king's older sister, did not come - at 91 and with health issues, she stayed in England.

The foreign guests were the barometer of who is on whose side at this moment. Queen Sofia of Spain (coming for the gala dinner), King Frederik and Queen Mary of Denmark, Grand Dukes Guillaume and Stephanie of Luxembourg, King Rama X and Queen Suthida of Thailand, King Philip and Queen Margarita of Serbia, Finland's president Alexander Stubb. From Liechtenstein, Norway, Belgium - all came.

Princess Sofia drew particular attention with a wide hat covering her eyes - elements some compared to Melania Trump at the inauguration. When a hat becomes political news, that says something about how little real news there is at such events and how much the guests are arranged for the camera.

Carl Gustaf is a relic of a Europe slowly disappearing - a monarch with limited constitutional power, but enormous symbolic value. Sweden is not the United Kingdom or Spain: here the institution has gone through controversy, particularly around the inheritance law amended in 1980 to allow the first-born daughter to inherit. Victoria is the result of that reform.

Are these ceremonies only theatre, or are they a serious diplomatic ring of meetings? When twelve European monarchies and a few global ones gather in one place, the negotiations happening in the corridors matter more than the Te Deum in the chapel. The Balkans, which no longer offers monarchies except symbolically, can only watch the remnants of the old continental order keep up their rituals.