Following the death in February 1733 of King Augustus II of Poland, European powers exerted diplomatic and military influence in the selection of his successor. Competing elections in August and October 1733 elected Stanisław Leszczyński and Frederick August, Elector of Saxony to be the next king. Stanisław was supported primarily by France, while Frederick August was supported by Russia and the Habsburg Emperor Charles VI. On October 10, France declared war on Austria and Saxony to draw military strength away from Poland, and shortly thereafter invaded both the Rhineland and the Habsburg territories in what is now northern Italy. The Italian campaign was conducted in conjunction with King Charles Emmanuel III of Sardinia, to whom France had promised the Duchy of Milan in the Treaty of Turin, signed in September 1733.
The Franco-Sardinian allies marched on Milan in October 1733, and occupied Lombardy without significant losses. In the spring of 1734 the Austrians responded in force, but suffered a bloody defeat in the Battle of San Pietro, won by the French under de Coigny and de Broglie. Following the victory, reluctance on the part of Charles Emmanuel to pursue the retreating Austrians led to relatively little action throughout the summer of 1734. In September Field Marshal Dominik von Königsegg-Rothenfels, who replaced Florimund Mercy (killed at San Pietro), renewed the Austrian offensive, winning a small victory near Quistello when his troops successfully raided de Broglio’s headquarters on 14 September, taking 1,500 prisoners and capturing Charles Emmanuel’s silver service and campaign warchest. As the Austrians pursued the allies, they surrounded additional pockets of soldiers, taking another 3,000 prisoners. The allies fell back toward Guastalla, where they fortified a position between the Crostolo and Po rivers.
After pausing to reprovision on 16 September, Königsegg continued the pursuit, reaching Luzzara on 18 September. The allied leadership that evening decided to force a battle at Guastalla as revenge for the action at Quistello.
The area between Guastalla and Luzzara included two small dams, and numerous other landworks, including hedges and low stone walls, that were useful as cover for defending troops. To the west of Guastalla was a plain dotted with copses of trees, extending to the Po, where the allies had a boat-bridge to facilitate the movement of troops across the river. Between the bridgehead and the fortified town of Guastalla they erected a series of defensive works between the two dams, anchored by a large redoubt about halfway between the town and the bridge. The allied line extended from the village of Pieve, south of Guastalla, around to the east and north of the town, ending with battalions of cavalry on the plains in front of the defensive line between the town and the bridge. Overall command was given to Charles Emmanuel, who led the center, with de Coigny leading the right flank and de Broglie the left. On the morning of 19 September Charles Emmanuel sent three regiments across the Po to guard against possible Austrian flanking maneuvers that could bypass his army and gain access to Milanese territory. Demonstrations by Austrian troops on the left bank of the Po on 18 September reinforced his concern over this possibility.
When Königsegg learned of this latter movement, he decided the time had come to attack the allied position at Guastalla, hoping for a decisive defeat, forcing the allies to retreat either across the Po or the Crostolo. Because he had been unable to personally reconnoiter the enemy position, and reports indicated no significant massings of enemy troops (which were largely concealed behind the numerous structures along the line of defense), Königsegg eventually concluded that the bulk of the allied troops had been withdrawn across the Po. Hoping to isolate the remaining enemy troops, he directed the bulk of his forces toward the bridgehead on the allied left.