Incest is a serious taboo across many cultures around the world, but you may not believe just how much incest there has been throughout history. Cousins marrying cousins, mothers and sons, daughters and fathers, distant relatives of all sorts — incest in history is not as uncommon as one might think.
Beyond the taboo act of incest, the powerful figures who partook in incest span across all types of nobles. It's not all just incest to keep power in the family: Intellectuals and scholars participated as well, and even a US president.
We know of a few of the cases of modern incest, including famous figures from Hollywood who were either consensual partners in incest or victims of incest, but the picture of historical incest is slightly more muddled, as there was typically no official database or record of who married whom.
All of the incest on this list is either documented in some form or strongly alleged — and none of it was written by George R.R. Martin.
Cleopatra, Egyptian pharaoh, married both of her brothers Ptolemy XIII and Ptolemy XIV, keeping with royal Egyptian tradition. In addition to these marriages, she may have killed one or both of the brothers as well.
Charles Darwin introduced the world to the theory of evolution. Some of his children — born from his marraige with his first cousin Emma Wedgwood — were born with abnormalities, something he suspected inbreeding as a likely reason for their genetic outcomes.
After marrying her cousin Prince Albert, Queen Victoria established a tradition of inbreeding for her descendants. She arranged her children and grandchildren into incestuous marriages throughout Europe because she thought it was a surefire way to ensure peace and prosperity throughout the continent. World War I challenged this diplomatic strategy.
Albert Einstein married his first cousin Elsa Lowenthal not long after divorcing his first wife. Many consider Elsa to be his closest partner — she helped nurse him back to health after a serious illness in 1917, and they emigrated to the US together as refugees when the Nazi party came to power in Germany.