Idioms: Blue Blood

What is the origin of the idiom “Blue Blood?”

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  1. The blood of hemophiliacs has a slightly blue tinge, and was used to refer to the vast numbers of Queen Victoria’s descendants with the disease.
  2. Noble families of Castile claimed that their blood was undliluted with other races, as evidenced by its blue color in their veins, easily seen through their pale skin.
  3. The Greek physician Hippocrates proposed that a person’s personality depended on the balance of body humors, one of which was blood.  Blue blood identified those with thoughtful intelligence.
  4. Debrett’s Peerage is a compilation of all the titleholders in England, and was often consulted to determine the “bloodstock” of a woman; i.e. whether a man was marrying above or below his station.  The covers of the book is a distinctive bright blue, and thus families in the book are referred to as “blue bloods.”