In that circumstance and sense, Charles was a casualty of the fierce factional infighting in the French court between the King's brother Gaston d'Orléans, and Cardinal Richelieu, even though technically, Lorraine was subject to the Holy Roman Empire and the Emperor Ferdinand II of Austria. Forced to make humiliating concessions to France, he abdicated under the French pressure and invasion in 1634 in favor of his brother, Nicholas Francis, and entered the imperial service in the Thirty Years' War and was victorious at the Battle of Nördlingen. Shortly thereafter, Nicholas Francis too fled into exile and abdicated his claims, which were now taken up once again by Charles, who remained Duke of Lorraine in exile for the next quarter century.