Charles V Leopold, duke of Lorraine (1643-1690) military and political career was strongly attached to the early modern history of Hungary, because of his important role played as commander in chief during the Great Turkish War of 1683-1699. The aim of this study is to explain the role played by Charles V of Lorraine in the reconquest of Hungary and in the formation of a new relationship between Hungary and the Habsburg Empire. Thanks to this Journal, we can get a much more detailed overview about the military and political career of Charles V, Duke of Lorraine, one of the main actors of the liberation of Hungary from the Turkish occupation. It allows us to have a better understanding of the specific activities of the Duke, such as the organisation and command of the army, as well as the political role of the Duke as a military officer. Finally, we focus on the issue whether he could benefit at the occidental theatre of wars from his experiences obtained in Hungary by the application of the small war.