Behind every successful man is a strong woman. So goes the well-known saying on the nature of patriarchy. In the case of many powerful historic leaders this support came from more than just one woman: as well as a wife, it often included one or possibly several mistresses. The image of the famous mistress in history is an ambiguous one. Her Cinderella-like life-story has, over the centuries, attracted public fascination. Yet simultaneously she has borne the taint of impropriety, or even illegality from her participation in a moderately tolerated form of bigamy. As a result, mistresses have often been the object of malice and resentment, even to the extent of being held responsible for a nation's misfortune. In societies where marriage was governed by rigid social rules, mistresses had a passport to rise swiftly to the highest social circles. They sometimes came from the class of the gentry or the bourgeoisie; in eastern harems even slaves were known to eventually rise to supreme power. But a mistress's career, so dependent on her association with a powerful man - a king, a sultan, or even a Pope, was fundamentally insecure. She had to possess highly-developed survival skills to maintain her position. Our drama documentary series traces the stories of famous mistresses in world history, narrated from their own point of view. These were extraordinary women who decisively influenced the course of history and deserve a place in the annals of the past in their own right, not merely as the lovers of famous men. Recent largely-unpublished research from, amongst others, Italy, the Netherlands and the United States, debunks many myths about mistresses with findings that show they provided an indispensable role: as confidantes, advisers and sources of strength, without them many rulers would have failed. Against the tide of popular opinion, their intervention was in many cases politically astute and beneficial.