Each time the Swedish royals have appeared this month in their glittering finery, they’ve also been wearing the light blue sash of the nation’s highest-ranking order of chivalry, the Royal Order of the Seraphim.

King Fredrik I of Sweden (source)

The current incarnation of the order was established in 1748 by King Fredrik I of Sweden. The announcement of the order declared that it was a revival of an older order of chivalry using the same name, but to my knowledge, there’s never been a clear connection to any earlier order of Swedish chivalry called the “Order of the Seraphim,” so that may have simply been a way to try to assert the order’s historical legitimacy. Either way, King Fredrik is still remembered on the insignia of the order used today, which bears the initials FRS, for “Frederik, King (Rex) of Sweden” on the reverse side of the medallion.

For many years, the Seraphim was an order of chivalry that was open to a number of possible recipients, with a complicated induction ceremony and a set of ceremonial habits. (Intriguingly, Seraphim knights also used to have supervisory roles with various hospitals and institutions in Sweden.) But Sweden’s chivalric orders went through a series of reforms in 1975, and today, the only Swedes who can become knights of the Seraphim are members of the royal family.

The order can also be conferred on foreign citizens; in practice, this means heads of state and members of foreign royal families (usually the monarch, his/her consort, and the heir, but usually not the heir’s spouse). The order has only one class. Men of the order are called “knights,” while women are called “members.”

But although the order has gone through a number of changes, the insignia has, with a few aesthetic changes, stayed largely the same, consisting of a collar, a badge, a sash, and a star. The collar features alternating blue patriarchal crosses and elaborate golden angel heads. (The seraphim, according to biblical tradition, are a high-ranking order of angels.)

The badge, which can be worn suspended from either the collar or the light blue sash, is in the shape of a Maltese cross with a blue medallion on its center. While the back of the medallion honors King Fredrik I, the front features the initials IHS, the monogram of Christ. The star is basically the same as the badge; however, the badge’s cross is also topped by a golden crown.

Traditionally, male members of the Swedish royal family received the order at their baptisms, but after the 1975 reforms, the family began giving the order to all members of the family, male and female, on their eighteenth birthday.

Those who become royal by marriage, like Queen Silvia and Prince Daniel, generally receive the order on or around their wedding days. Daniel actually got his insignia on the way out of the church after he married Crown Princess Victoria, between the walk back down the aisle and the couple’s appearance at the church door.

However, King Carl XVI Gustaf has recently revived the baptismal tradition, presenting miniature versions of the Seraphim insignia to his granddaughters, Princess Estelle and Princess Leonore, at their baptisms. We can expect a new knight or member of the order the next time one of Carl XVI Gustaf’s children has a child — and there will also be a new member next summer, when Sofia Hellqvist marries Prince Carl Philip.