Royal Harlot: A Novel of the Countess of Castlemaine & King Charles II by Susan Holloway Scott (methinks she also wrote the bionovel of Sarah Churchill) was pretty good (except for that whole first-person narrative thing ). Scott makes the notorious Barbara Villiers a likeable peep
Apparently the poor thing has a miserable childhood after her father's death & was farmed out to paid watchers until the age of 15, when her remarried mother called her to London because she was of suitable age to attract a rich hubby. Instead, Barbara had a torrid affair with the womanizing Earl of Chesterfield, among others. Mamma wasn't upset that Barbara was fooling around, just that it might reduce her value to a potential husband if word got out. She married Roger Palmer right around the time Old Noll died, & Roger was an ardent Royalist who put his wife into temptation's way by agreeing to send her as a courier to Charles IIs court in exile at Brussels, where her liaison with the wannabee king begins.
Paternity of Barbara's 1st & last children (Anne & Barbara) are disputed; Anne was acknowledged as Roger's heiress & always went by Palmer, never Fitzroy like the rest of them, & Charles allegedly knew the youngest wasn't his but suggests to his mistress that the child be known as a Fitzroy also to save face. However, Charles, Henry, Charlotte, & George were all supposedly really the king's get.....how anyone could be certain with the amount of fornication my Lady Castlemaine did was astonishing LOL She was definitely a woman ahead of her time who didn't get why it was OK for men to jump from bed to bed & not women, & realized that with her wussie spouse the only way to get ahead in the Restoration world was to use her body for gain.
The authors says the reason the Palmers received an Irish title was because, unlike an English one, it didn't have to be approved by Charles's chancellor, Hyde, who apparently hated her guts as much as Wolsey hated Anne Boleyn's.....though probably not as much as Catherine of Braganza did, as much is made of the royal tantrums that ensued when Barbara was named Lady of the Bedchamber. Couldn't have been much fun for the queens to have their hubby's mistresses dancing attendance on them as well.
Despite her volatile temperament & publicized quarrels with Charles, methinks Barbara had a nice long run as "favorite" considering what a lecher Charles was. You just kinda picture him running all over London wearing himself out visiting Nelly Gwyn & Louise de Keroualle & Barbara herself & the queen & then having some actress sneaked up the back stairs for a one-night stand LOL
The book ends where Barbara finally realizes she's no longer the favorite & runs off to the continent after breaking it off with Charles, though Scott does have an afterword that tells you what happened the rest of her life