War of the Polish Succession

French mounted grenadiers of Louis XV

When hostilities finally broke out, the Austrians had hoped for aid from the maritime powers, Great Britain and the Dutch Republic. They were disappointed in this, since both the Dutch and the British chose to pursue a policy of neutrality. The British Prime Minister Sir Robert Walpole justified Britain's non-intervention by insisting that the Anglo-Austrian Alliance agreed at the 1731 Treaty of Vienna was a purely defensive agreement, while Austria was in this instance the aggressor. This position was attacked by English Austrophiles who wanted to aid the Austrians against France, but Walpole's dominant position ensured that Britain stayed out of the conflict. The Dutch under the leadership of Grand Pensionary Simon van Slingelandt mediated between the parties, but were anxious themselves to not have war on their doorstep again. The heavy toll of the previous wars against France on the Dutch economy was still in fresh memory.[4] The threat of war still forced the Dutch Republic to increase the size of its army, just at a time the Dutch had hoped to be able to reduce it appreciably.[5] The French however wished not to provoke Britain and the Dutch Republic and carefully chose not to campaign in the Austrian Netherlands and parts of the Holy Roman Empire that might draw either power into the conflict.

A Dutch army officer in 1725

On Austria's southern border, France in November 1733 negotiated the secret Treaty of Turin with Charles Emmanuel and prepared for military operations in northern Italy. It concluded the (also secret) Treaty of the Escorial with Spain, which included promises of French assistance in the Spanish conquest of Naples and Sicily. France also made diplomatic overtures to Sweden and the Ottoman Empire in a fruitless attempt to draw them into the conflict in support of Stanisław.

The Austrians were thus left largely without effective external allies on their southern and western frontiers. Their Russian and Saxon allies were occupied with the Polish campaign, and the Emperor distrusted Frederick William I of Prussia, who was willing to provide some aid. Divisions within the empire also affected the raising of troops in 1733, as Charles-Albert of Bavaria, who harbored ambitions to become the next Holy Roman Emperor, signed a secret agreement with France in November 1733, and tried, with limited success, to dissuade other rulers within the empire from the Wittelsbach family from providing troops to the emperor under their treaty obligations. While Britain itself did not provide support, the Electorate of Hanover, where George II also ruled as an Imperial Elector, proved willing to help. On 9 April 1734, a Reichskrieg (imperial war) was declared against France, obliging all imperial states to participate.

Russian grenadier in 1732

The Russians, commanded by Peter Lacy, quickly captured the capital city of Warsaw and installed Augustus as potential heir, forcing Stanisław to flee to Danzig (present-day Gdańsk), where he was besieged for some time by a Russian-Saxon army that came under the overall command of Field Marshal Burkhard Christoph von Münnich. Danzig capitulated in June 1734, and Stanisław was forced to flee once more, this time first to the city of Königsberg and eventually to France. This ended major military activity in Poland itself, although it continued to be occupied by foreign troops as Augustus dealt with partisan supporters of Stanisław. A group of nobles and aristocrats supporting Stanisław formed the Confederation of Dzików in late 1734, and under their commander, Adam Tarło, tried to fight the Russian and Saxon troops, but their efforts were ineffective. In what became known as the Pacification Sejm, held in June–July 1736, Augustus was confirmed as King of Poland and Grand Duke of Lithuania.

Following France's October 10 declaration of war, it began military operations three days later, invading the Duchy of Lorraine and besieging the imperial fortress at Kehl, across the Rhine from Strasbourg, gaining control of both objectives in a few weeks. Unable to attack Austria directly, and unwilling to invade the intervening German states for fear of drawing Great Britain and the Dutch into the conflict, France consolidated its position in Lorraine, and withdrew its troops across the Rhine for the winter.

The emperor mobilized his active forces in response to the French attacks, and began the process of calling up the Army of the Holy Roman Empire, establishing a defensive line at Ettlingen, near Karlsruhe. In the spring of 1734 French maneuvers successfully flanked this line, and Prince Eugene of Savoy was forced to withdraw these forces to the imperial encampment at Heilbronn. This cleared the way for the French army under the Duke of Berwick to besiege the imperial fort at Philippsburg, which fell after a siege of two months in July 1734. Eugene, who was accompanied by Crown Prince Frederick of Prussia, made some attempts to relieve the siege, but never made any decisive attacks against the besieging army owing to its size and the relatively poor quality of the troops under his command. Berwick was killed by a shell at Philippsburg.

French armies continued to advance along the Rhine, reaching as far as Mainz, but the growing imperial army, which came to include troops from Russia that had assisted with the capture of Danzig, was able to prevent France from establishing a siege there, and Eugene went on the offensive. A force of 30,000 under Friedrich Heinrich von Seckendorff crossed the Rhine and began pushing the French back toward Trier, defeating them at Clausen in October 1735, in one of the last battles before preliminary peace terms were reached.

French and Savoyard troops numbering over 50,000, under the command of Charles Emmanuel, entered Milanese territory as early as October 24, against minimal resistance, as the Austrian forces in the duchy numbered only about 12,000. By November 3, the city of Milan itself had surrendered, although the Austrian governor, Count Wirich Philipp von Daun, still held the fortress. France's great general, the Duke de Villars, joined Charles Emmanuel in Milan on November 11. While Villars wanted to move immediately against Mantua to secure the Alpine passes against Austrian reinforcements, Charles Emmanuel, mistrustful of his French allies and their dealings with Spain, sought to secure Milan. The army spent the next three months eliminating Austrian opposition from the remaining fortified towns in the duchy. Villars attempted to interest Don Carlos of Parma in joining the expedition against Mantua, but Carlos was focused on the campaign into Naples. Villars began to move against Mantua, but Charles Emmanuel resisted, and the army made little progress. In early May, an Austrian army of 40,000 under Count Claude Florimond de Mercy crossed the Alps and threatened to close in on the French army's rear by a flanking maneuver. Villars responded by retreating from Mantua and attempted without success to interrupt the Austrian army's crossing of the Po. Villars, frustrated by Charles Emmanuel's delaying tactics, quit the army on May 27. He fell ill on the way back to France and died in Turin on June 17.

Charles Emmanuel III of Sardinia, 18th century engraving

Mercy's forces made repeated attempts to cross the Parma river in June, but it was not until late in that month that they were able to cross the river and approach the city of Parma, where the allied forces, now under the command of French marshals de Broglie and Coigny, were entrenched. In the Battle of Colorno and in a bloody battle near the village of Crocetta on June 29, the Austrians were beaten back, Mercy was killed, and Frederick of Württemberg, his second, was wounded. Charles Emmanuel returned the next day to retake command, and resumed his delaying tactics by failing to immediately pursue the retreating Austrians. The Austrians retreated to the Po, where they were reinforced by additional troops and placed under the command of Field Marshal Königsegg. After two months of inaction, during which the armies faced each other across the Secchia river, Königsegg on September 15 took advantage of lax security and executed a raid on Coigny's headquarters at Quistello, very nearly capturing Coigny and taking among other prizes Charles Emmanuel's china. Two days later the French withdrew to a position near Guastalla in response to Austrian maneuvers, but one detachment of nearly 3,000 men was surrounded and captured by the advancing Austrians. On September 19, Königsegg attacked the allied position at Guastalla, and in another bloody encounter, was beaten back, losing among others Frederick of Württemberg. Königsegg retreated across the Po, adopting a defensive position between the Po and the Oglio while Charles Emmanuel again did not capitalize on his victory. When he finally withdrew most of the allied army to Cremona, the Austrians advanced on the north bank of the Po as far as the Adda before both armies entered winter quarters in December 1734.

In southern Italy, the Austrians, choosing a strategy of defending a large number of fortresses, were soundly defeated. Don Carlos assembled an army composed primarily of Spaniards, but also including some troops from France and Savoy. Moving south through the Papal States, his army flanked the frontline Austrian defense at Mignano, forcing them to retreat into the fortress at Capua. He was then practically welcomed into Naples by the city fathers, as the Austrian viceroy had fled toward Bari, and the fortresses held by the Austrians in the city were quickly captured. While maintaining a blockade of the largest Austrian fortresses at Capua and Gaeta, a large portion of the allied army gave chase to the remaining Austrian forces. These finally attempted a stand in late May, and were defeated at Bitonto. Capua and Gaeta were then properly besieged while Austrian fortresses in Sicily were quickly subdued. Gaeta surrendered in August, and Capua held out until November when its commander, Otto Ferdinand von Abensberg und Traun, finally negotiated surrender terms when he ran out of ammunition. The Jacobite pretender's heir, Charles Edward Stuart, who was under 14 then, also participated in the French and Spanish Siege of Gaeta, making his first exposure to battle.

The armies in northern Italy suffered significantly over the winter, with significant losses to disease and desertion. For the 1735 campaign the allied forces in northern Italy came under the command of the Duke de Noailles, elevated to Marshal after his successful contributions to the Rhine campaign. They were also joined by Spanish forces in May, now available after the successes in the south. In response to this threat, Königsegg retreated into the Bishopric of Trent, but leaving the fortress city of Mantua well-defended. At this point divisions between the allies became clear, as Spain laid claim to Mantua, and also refused to guarantee Milan to Charles Emmanuel. In response, Charles Emmanuel refused to allow his siege equipment to be used against Mantua. As a result, the Franco-Spanish army was unable to do more than blockade the city. When Charles Emmanuel withdrew his forces from the area, the allies were forced to retreat, and the beleaguered Austrians capitalized, eventually recovering most of Milan against little opposition in November.