Haemophilia figured prominently in the history of European royalty in the 19th and 20th centuries. Britain's Queen Victoria, through two of her five daughters, Princess Alice and Princess Beatrice, passed the mutation to various royal houses across the continent, including the royal families of Spain, Germany, and Russia. Victoria's youngest son Prince Leopold, Duke of Albany, also suffered from the disease, though none of her three elder sons did. For this reason, haemophilia B was once popularly called "the royal disease". Tests on the remains of the Romanov imperial family show that the specific form of haemophilia passed down by Queen Victoria was probably the relatively rare Haemophilia B.