Laudon, Or London, Gideon Ernst, baron, an Austrian general, born at Trotzen, Livonia, Oct. 10, 1716, died at Neutitzschein, Moravia, July 14, 1790. He was descended from an ancient Scottish family, settled for several centuries in Livonia, and at 15 years of age entered the Russian military service, from which he retired after the peace of Belgrade in 1739, with the rank of lieutenant. Having unsuccessfully applied to enter the service of Frederick the Great of Prussia, he went to Vienna, and received in 1742 a captain's commission in Trenck's corps of pandours, and fought with reputation in the campaigns of Bavaria and the Rhine in 1742-'4. At an affair of outposts near Saverne he was wounded and taken prisoner, but was exchanged, and participated in the second Silesian war against Prussia. Disgusted with the cruelties of his commander, he left the corps, and after the peace of Dresden (1745) remained for several years in obscurity and poverty. Having at length procured a major's commission in a regiment stationed on the Turkish frontier, he married, embraced the Catholic religion, and devoted much time to the study of mathematics and tactics.

At the breaking out of the seven years' war he was appointed lieutenant colonel of a partisan corps charged with supporting the movements of the Austrian army, and in a single year, by his activity, courage, and capacity, acquired the rank of general, notwithstanding that the battles in which he participated were generally disastrous to the Austrians. His commission of general having fallen into the hands of Frederick, the latter sent it to him with a congratulatory letter. In 1758 he contributed to raise the siege of Olmtitz, and harassed the retreat of Frederick, receiving for his services the rank of lieutenant field marshal. The next year he crossed the Brandenburg frontier to cover the operations of Marshal Daun, and ended a series of brilliant exploits by deciding the rout of the Prussians at the decisive battle of Kunersdorf, Aug. 12, 1759. Receiving the rank of Feldzeugmeister, he gained the battle of Landshut, June 29, 17(50, took the fortress of Glatz, and covered the retreat of Daun after the Austrian defeat at Liegnitz, Aug. 15, with so much skill that Frederick exclaimed: "We must learn from Laudon how to retreat; he leaves the field like a conqueror." He crowned his achievements in the seven years' war by taking by assault, without previous investment, Oct. 1, 1761, the important city of Schweidnitz, filled with provisions and munitions of war.

During the peace which succeeded he was employed with credit in various public capacities, and in 1766 became a member of the aulic council of war, and in 1769 commandant general of Moravia. For a number of years he lived in retirement at his estate near Vienna, devoting himself to his favorite studies; but upon the breaking out of the Bavarian war of succession he took the field in Bohemia, and by a skilful concentration of his forces on the Isar prevented a junction between Prince Henry of Prussia and Frederick, thereby securing a decided advantage to the Austrians. In 1778 he was made field marshal. His military career terminated with the campaign against the Turks in 1788-'9, the first act of which he brought to a successful conclusion by the capture of Belgrade, for which he was appointed generalissimo. He died soon after removing to his headquarters in Moravia, whither the emperor Leopold II. had sent him after the Turkish war. He was simple in his manners and tastes, averse to securing influence by flattering the weaknesses of the great, and beloved by his troops.