A young captain at Leuthen, he found himself suddenly in command of 200 men, the battalion colonels and majors having been killed, and led them to shelter from Prussian cannon fire beside a windmill; subsequently, he participated in the retreat to Königsburg.

[7] He became the intimate friend and counselor of Emperor Joseph II, and, inheriting his father's vast estates, lived in the greatest splendor and luxury until the War of the Bavarian Succession brought him again into active service.

In 1778, de Ligne was impressed by a captured Prussian officer Flemming von Hagen, who was asked about his girl friends by his captors and replied, "I love nothing more dearly than my sword".

[8] King Frederick the Great of Prussia built a number of palaces and other buildings in Potsdam, but upon closer inspection, the place had a seedy appearance.

de Ligne wrote that Frederick had a chance to do something new in Potsdam, but "he believed that he could bend Nature to his will by the force of his intellect, in the same way as he attained his victories, and managed war, politics, population, finances and industries.

[9] This war was short and uneventful, and the prince then traveled in England, Germany, Italy, Switzerland and France, devoting himself impartially to the courts, the camps, the salons and the learned assemblies of philosophers and scientists in each country.

Shortly after the siege of Belgrade, he was invited to place himself at the head of the Belgian revolutionary movement, in which one of his sons and many of his relatives were prominent, but declined with great courtesy, saying that "he never revolted in the winter."

Though suspected by Joseph of collusion with the rebels, the two friends were not long estranged, and after the death of the emperor the prince remained in Vienna.

His Brabant estates were overrun by the French in 1792–93, and his eldest son killed in action at La Croix-du Bois in the Argonne (14 September 1792).

De Ligne served as captain of the Trabanten Life Guard (Gentlemen at Arms) and the Hofburgwache (Palace Bodyguard) from 13 June 1807 until his death.

He lived long enough to characterize the proceedings of the Congress of Vienna with the famous mot: "Le Congrès ne marche pas, il danse."

Selections were published in French, German and English: The most important of his numerous works on all military subjects is the Fantaisies et préjuge's militaires, which originally appeared in 1780.

This work, though it deals lightly and cavalierly with the most important subjects (the prince even proposes to found an international academy of the art of war, wherein the reputation of generals could be impartially weighed), is a military classic, and indispensable to the students of the post-Frederician period.

; Peetermans, Le Prince de Ligne, ou un écrivain grand seigneur (Liege, 1857), Etudes et notices historique concernant l'histoire des Pays Bas, vol.