Stephanie is wearing a tiara that belongs to her family.
Crown Princess Mary is wearing one of my favourite tiaras here. The Ruby Parure Tiara. This tiara belonged to Crown Prince Frederik’s grandmother, Queen Ingrid. The set has a necklace, earrings, brooch and a ring. (Source)
It has a long and interesting history with the Danish Royal Family - You can read more about that here.
“Queen Victoria’s Emerald and Diamond Tiara” designed by her husband , Prince Albert, in the Gothic style.
Empress Alexandra Feodorovna’s diamond and aquamarine kokoshnik tiara.
Empress Alexandra Feodorovna’s diamond and emerald tiara created by jewelers Bolin and Fabergé (1900).
Empress Maria Feodorovna’s diamond and sapphire diadem “Russian Beauty.”
Russian Imperial Wedding Tiara.