Hemophilia became known as the "royal disease" due to it being
passed through the descendants of Queen Victoria and Prince
Albert of Great Britain and Ireland. When Prince Leopold was born,
he was the first member of the royal family to have the disease. He
was the 8th child born to Victoria and Albert. No one in the royal
family previously had the disease. Because members of royal
families are encouraged to marry others of royal blood, the disease
spread throughout the members of the noble families of Europe
and Russia.
A partial pedigree chart of the family is shown below.