Royalty is sometimes called “blue blood” because of the blue-colored veins that are more visible in fair-skinned people, such as those of European aristocratic and royal families. The term originates from the Spanish phrase “sangre azul,” which translates to “blue blood.”
During the Middle Ages, European royalty and nobility were thought to have “pure” or “noble” blood, which meant that their lineage was untainted by commoners or peasants. This belief was based on the notion that royalty and nobility were descended from ancient gods and heroes, and that their blood was inherently superior to that of the common people.
As a result, these individuals were often physically distinguished from the rest of the population by their fair skin, which made the blue veins in their bodies more visible. This physical trait came to be associated with nobility and royalty, and the term “blue blood” eventually became synonymous with these groups.
In addition to their fair skin, royalty and nobility were often distinguished by their elaborate clothing, jewelry, and other symbols of wealth and status. They also lived in grand palaces and castles, and were served by armies of servants and attendants.
The belief in the superiority of noble blood persisted throughout much of European history, and was reinforced by various social and political structures, such as the caste system in India and the feudal system in Europe.
However, the concept of “blue blood” as an indicator of purity or superiority has been challenged in modern times, as scientific research has shown that all human beings have essentially the same blood composition, regardless of their social status or lineage.
Today, the term “blue blood” is often used in a more symbolic or metaphorical sense, to refer to those who are born into privileged or aristocratic families, or who occupy positions of power and influence in society.