As commander of the Coalition's left flank in the Adige campaign in northern Italy in 1799, he was instrumental in isolating the French-held fortresses on the Po River by organizing and supporting a peasant uprising in the countryside.

Johann Josef Cajetan von Klenau und Janowitz was born into an old Bohemian nobile family at Benatek Castle[2] in the Habsburg province of Bohemia on 13 April 1758.

His regiment repulsed an attack of superior numbers of Ottoman forces on 28 September 1788, at Zemun, near Belgrade, for which he received a personal commendation and earned his promotion to major.

[11] On 12 February 1793, Klenau received his promotion to lieutenant colonel in a Lancer regiment, and joined the Austrian force in the Rhineland, serving under General of Cavalry Count Dagobert Sigmund von Wurmser.

At the first Battle of Wissembourg, Klenau commanded a brigade in Friedrich, Baron von Hotze's 3rd Column on 13 October 1793, during which the Habsburg force stormed the 19 kilometers (12 mi) earthen ramparts held by the French.

On 24 September 1795, seeing the French, with five battalions and a regiment of Chasseurs overwhelming the troops of General Adam Bajalics von Bajahaza, Klenau quickly organized his own brigade into three columns and attacked.

[33] Instructed to block the Austrians from access to the Swiss alpine passes, Jourdan planned to isolate the armies of the Coalition in Germany from allies in northern Italy, and prevent them from assisting one another.

By crossing the Rhine in early March, Jourdan acted before Charles' army could be reinforced by Austria's Russian allies, who had agreed to send 60,000 seasoned soldiers and their more-seasoned commander, Generalissimo Alexander Suvorov.

Furthermore, if the French held the interior passes in Switzerland, they could prevent the Austrians from transferring troops between northern Italy and southwestern Germany, and use the routes to move their own forces between the two theaters.

[35] At the same time, the Army of Switzerland, under command of André Masséna, pushed toward the Grisons, intending to cut the Austrian lines of communication and relief at the mountain passes by Luziensteig and Feldkirch.

[42] The peasant uprisings pinned down the French and, by capturing Ferrara, Klenau helped to isolate the other French-held fortresses from patrols, reconnaissance, and relief and supply forces.

[43] In early 1800, Klenau transferred to the K(aiserlich) und K(oeniglich) (Imperial and Royal) army of Germany, in Swabia, under the command of Feldzeugmeister Paul, Baron von Kray.

[46] Stockach, at the western tip of Lake Constance, covered east–west and north–south crossroads; it and near-by Engen, only 20 kilometers (12 mi) west, had been the site of a French loss 14 months earlier.

[49] From 1801 to 1805, during which Austria remained aloof from the ongoing friction between Britain and Napoleon's France, Klenau commanded a division in Prague, and was named as Colonel and Inhaber of the 5th Dragoon Regiment.

Here, 12 kilometers (7 mi) northeast of Ulm, and slightly north of the Danube, Ney's VI Corps (20,000 men) captured half of the Austrian Reserve Artillery park at Thalfingen.

[58] At this point, the entire Austrian force, including Klenau's column, withdrew into Ulm and its environs and Napoleon himself arrived to take command of the II, V, VI Corps, Ney's Cavalry and the Imperial Guard, numbering close to 80,000 men.

Again, as he had been at Mantua, Klenau was caught in a siege from which there was no escape, and again, he helped to negotiate the terms, when, on 21 October, Karl Mack surrendered the encircled army of 20,000 infantry and 3,273 cavalry.

[67] The disaster at Eckmühl was followed by another at Regensburg (also called the Battle of Ratisbon) on 23 April, where Klenau, at the head of six squadrons of Merveldt's Uhlanen (lancers), was crushed and scattered by Étienne Marie Antoine Champion de Nansouty's heavy cavalry.

Klenau managed a spirited, and gradual withdrawal to a position behind the Austrian line at the Russbach, and above the Wagram escarpment; this exposed several of the villages on the western edge of the Marchfield Plain, including Aspern and Essling, to French capture.

[76] On the next day of battle, Klenau was ordered to a forward position, to complete a double-envelopment of Napoleon's force, envisioned by Charles as the best means of inducing panic among the French troops.

There was no support from Kollorat's forces on his flank, and for the closing prong of the pincer movement, Archduke John was nowhere in sight; he had not abandoned his baggage, and was plodding slowly, with his army, toward the battlefield, but still a good day's march away.

General René Savary, who directed part of the French pursuit, wrote that the Klenau's soldiers had "fought in a manner calculated to instill a cautious conduct into any man disposed to deeds of rashness.

Francis also agreed to pay an indemnity equivalent to almost 85 million francs, gave recognition to Joseph Bonaparte as the King of Spain, and affirmed Habsburg participation in Napoleon's Continental System.

A few weeks later, at the Battle of Bautzen, 20–21 May 1813, the combined Russian and Prussian force surprised Ney's corps in a confused assault, which narrowly escaped destruction when Napoleon appeared with reinforcements.

[85] The Armistice of Poischwitz, signed 4 June 1813, established a cease-fire throughout central and eastern Europe that was intended to last until mid-July; the combatants had to give six days' notice of its termination.

This theoretically accomplished two goals: Napoleon could not defeat them piecemeal, and the presence of soldiers from several states within a single armed force limited "politically motivated acts of national self-interest.

The Crown Prince of Sweden, Jean-Baptiste Bernadotte, a former Marshal of France and a favorite of Napoleon's, established an army of observation at Hamburg and Lübeck, and another 70,000 concentrated 50 kilometers (31 mi) southwest of Berlin.

As the Coalition assaulted the southern suburbs of the city, Napoleon arrived from the north and west with the Guard and Marmont's VI Corps, covering 140 kilometers (87 mi) in forced marches over three days.

He took the Kolmberg, a nearby height also known as the Schwedenschanze (Swedish fortification), a defensive remnant of the Thirty Years' War about 4 kilometers (2 mi) east of the village, and established a battery there, but did not bring enough troops to support it.

Marshal Laurent de Gouvion Saint-Cyr surrendered to Klenau on 11 November,[19] but Schwarzenburg refused to agree to the capitulation and the French troops marched into captivity into Austria instead.