Yvonne is a french nobleman’s daughter who has been kidnapped in her early teens and sold into a harem. When John reaches Karaman, the Emir does not want it to be known that he is being helped by an infidel he therefore creates a persona for John as a Prince of Islam. He gives John a small palace for his use and insists that he install a harem in the palace so that he remains in character. He gives Yvonne to John as his wife, something Yvonne herself has manipulated. As is the custom Yvonne then assists John in the selection of other members of his harem. Yvonne has been in a harem for over five years and thinks like a harem girl. It is, John discovers, all about politics. Yvonne will not tolerate anyone in the harem who will not accept her authority. In general she instructs John to select recently captured slaves who will be no threat as they will have no knowledge of the system. She rationalises this by saying that ultimately John will be able to give them freedom to return to their own homes, something she instinctively knows would appeal to him.
John feels totally comfortable with Yvonne and tells tells her about his relationship with Ximene. She is horrified. She plots to lure Ximene into the harem so that Ximene can be trained “how to honour her master”. The opportunity presents itself when John moves on to Grenada. He keeps the same alias and takes the harem with him.Inevitably when Ximene comes into the harem, not realising that Yvonne not John is the master within its walls, there is a ferocious clash. They eventually reach an honourable truce and they recognise in each other complementary talents. They become close associates for the rest of their lives. Ximene comes to rely on Yvonne for analsis of memale motivation, something she struggles with herself. They become so close that both Alyse and Phillipa feeling excluded start to use their influence against bothYvonne and Ximene.