Srowning favorites

It would be natural to expect from the favorites of the monarchs that they strive at all costs to maintain the favor of the august patron. However, in history, there are frequent cases when the favorites arose dissatisfaction with their benefactors, and they not only ceased to kiss the hand showered them with merits, but also attempted to rule this person.
Is Elizabeth I Tudor"s elderly queen really, the hand did not tremble the death sentence to his young favorite Robert Devereo, Count Essex? What prompted the wife of the two favorites of King Louis XIII, his wife Anna Austrian, the Duchess of Marie de Chevrez, to become an eternal, irreconcilable and indomitable opponent of the autocratic royal power? Why did the Queen of Great Britain Anna Stewart, the mother of 19 offspring, did not leave behind a direct heir? How was the rivalry of her two favorites, the Duchess of Sarah Malboro and Lady Abigail Mash, on the political life of Great Britain? - The answers to these tricky