100% actual history, documented in actual surviving Goya paintings (one of which is of a reclining nude woman):
During the 1788-1808 reign of King Charles IV, three of the most powerful women in Spain were carrying on simultaneous, torrid love affairs with 2 of most powerful men in the country.
The men:
> Manuel Godoy, Enlightenment Prime Minister of Spain
> Francisco Goya, possibly the greatest painter in the country's history
The women:
> Queen Maria Luisa (Charles IV's wife, who confoned her affair with Godoy to keep him in government service). Maria Luisa was born in 1751, and is not to be confused with Napoleon's second wife, also named Maria Luisa of Parma, who was actually a Hapsburg princess, but was born in 1791 and became Napoleon's 2nd wife in 1810. (The confusion between the 2 Maria Luisa's is the main reason this pentagon isn't better known.)
> Maria Pimental, Duchess of Osuna (the nude model for a famous Goya painting)
> Maria Cayetana de Silva , Duchess of Alba
The 3 women knew of each other and were bitter rivals. Alba's premature death was believed, at the time, to have been by poisoning.