Queen Kristina of Sweden (1626-1689) is a person who has been widely studied during the years. She is known as the monarch who left the Swedish throne and the protestant faith in favour of the catholic Rome. Even though Kristina left her powerful position as queen of Sweden she never gave up her dignity as a sovereign.   My purpose with this study is to analyse historians and other scholars different research concerning Kristina’s notorious execution of Monaldesco in 1657. This event took place during her time as a guest on Fontainebleau, the French king´s castle. In my literature study regarding this event I will apply the famous Italian humanist Niccolò Machiavelli’s advice on how to be a capable prince. With this mentioned my essay is named:  A Valiant Lion and a Cunning Fox. A Study on the Execution of Monaldesco from Machiavelli’s Theory of the Prince.   The Machiavellian theory of the prince is very complex. The demands to become an able prince according to Machiavelli are almost impossible to reach. However, in my study it becomes clear that Kristina was capable enough to capture Fortune when Jules Mazarin gave her the opportunity to join him in an alliance with the aim to conquer Naples. On the other hand, her choice did not only provide her with profits, it also put her in a position of dependence, a position which Machiavelli considers to be problematic. Furthermore, the literature claims that Kristina tried to use the cunning of a fox, the problem was that Mazarin was even more cunning the she was. Later the plans of conquering Napels was exposed by Kristina’s crown equerry Gian Rinaldo Monaldesco. The penalty for this crime he had to pay with his life, she executed him in Galerie des Cerfs on Fontainebleau. As a result of Kristina’s actions Europe got disturbed and a lot of rumours got spread which damaged her reputation badly. Nevertheless, Kristina took full responsibility of the execution. Machiavelli agrees on the fact that betrayal should be punished but the negative consequences gave Kristina a very bad reputation, and Machiavelli emphasizes that a capable prince should avoid being hated. My conclusion is that Kristina proves some minor signs of herself as a capable prince according to Machiavelli. However it should be pointed out that the capability that Machiavelli emphasizes is almost impossible to achieve. The study has also shown that, in contrast to Machiavelli’s capable prince, according to literature Queen Kristina´s foremost goal was nothing but her own independence and freedom.