CASTLE

Mistresses may have first come into favor when Kings were forced to marry and find their Queens among their relations - cousins. Some biologists theorize that people are not really that attracted to others who they share a close genetic relationship with. Over time the Royal Houses of Europe became closely related. A King may have mated with his Queen to keep the wealth and power, but found his true love in someone he chose whose genetics were very different... it was even believed that "Royal Bastards" - love children - turned out to have nicer personalities.... really!