'But my dear good people why do you follow me about? I am only just another soldier's wife.' So said Queen Louise of Prussia (1776 - 1810) when the court had pulled back to the town Naumburg on the Saale in the face of Napoleon's terrifying advance. It was charmingly disingenuous, as Constance Wright makes clear in this excellent biography, but with a deadly political purpose - solidarity with the subjects of her husband Frederick William III and to rally them in their darkest times to defy the French dictator and his army.

Napoleon in turn was fascinated and horrified by Queen Louise. She was a beautiful woman with an intelligent mind and good political instincts which she used against him. That he could not bear. For stepping out of what he perceived as her woman's sphere, he denigrated and maligned her as a previous generation had Marie Antoinette. Louise, by contrast, was much cleverer and more astute - there's an unforgettable scene as she rides at the head of Prussian troops through the Brandenberg Gate - and right and justice was on her side.

While she was active, political and ready for the fight her husband preferred to vacillate and aim for compromise. Their marriage was a love match that deepened and changed into something much more dynamic and relevant in a time of war. As she wrote to him: ‘Dear friend, how happy I am to have you here. It is always better for us to be together.’ Having convinced her husband to fight she wrote to the Russian emperor Alexander, 'We are treading the path of honour now, and it would be better to go under than to turn back.' She died at a tragically early age before she saw the liberation of her homeland.