On September 1, 1701, the Irish Brigade of France fights at the Battle of Chiari in northern Italy during the War of the Spanish Succession. The engagement is part of Prince Eugene of Savoy‘s campaign to seize the Spanish controlled Duchy of Milan in the Italian peninsula, and follows his victory over Marshal Nicolas Catinat at the Battle of Carpi in July. Marshal François de Neufville, 2nd Duke of Villeroy, replaces Catinat as commander of the Franco–Spanish–Savoyard forces in the theatre, carrying with him orders from King Louis XIV to push the Imperialists out of Italy.

Eugene welcomes the prospect of a decisive battle, and waits on the eastern side of the Oglio to be attacked. The Imperial commander has chosen his ground carefully, entrenching his troops and guns in front of the small fortress of Chiari. Streams protect his position on three sides so, as there is not enough room for a cavalry engagement, Eugene can count on a frontal attack by the French infantry. Two battalions and a few pieces of artillery are placed in Chiari itself.

Villeroy ignores Catinat’s warning that Eugene is in a strong position, remarking that the King, “had not sent so many brave men just to look at the enemy through their spy glasses.” On September 1, the Franco-Spanish infantry advances. Deceived by the report of spies that the Imperialists are retiring, Villeroy crosse the Oglio and pushes on to Chiari expecting to attack their rearguard. The attack begins around 2:00 p.m. when three French brigades approach Chiari and overpower the Imperial troops there without much difficulty. However, instead of facing the rearguard, the French commander encounters the whole Imperial army securely entrenched in their positions. As the Bourbons’ army approaches the Imperial positions, Eugene forbids his men to fire. Loading their artillery with canister shot, they only unleash a withering fire when the Bourbon army enters point-blank range. This disorders the attackers and chaos ensues which the French and Spanish commanders cannot suppress. While this is going on, Chiari is recaptured by the Imperials after a fierce struggle. The Bourbons are driven back with heavy casualties in a contest as destructive as any battle during the war in Italy. With only minor losses, the Imperial army inflicts over 3,000 casualties in the ranks, and over 250 officers. This number grows rapidly as fever attacks the wounded.

Villeroy loses personal control during the battle, and Catinat, despite being wounded, has to organise a retreat. The French dig themselves in only a mile or so away from the Austrians on the same side of the Oglio. Here, the two opposing sides remain for the next two months: the French are too much discouraged by their repulse to resume the assault, and Eugene is unwilling to risk the advantages he had gained by attacking the French in their strong defensive position. However, as autumn advances, conditions deteriorate in both camps: fodder is so short that Eugene’s horses are forced to eat fallen leaves. But the French, whose camp is built on marshy ground, suffers most, and they move out first in mid-November, crossing the Oglio before entering winter quarters in the Duchy of Milan.

In Milan, the French presence proves increasingly unpopular: five million French livres for soldiers’ pay and lodgings, and two million for fodder, has soon been imposed on the local population, most of which has to be taken by force. For his winter quarters, Eugene proceeds to reduce the whole Duchy of Mantua, except the capital and Goito, which he closely blockades. Shortly after he occupies Mirandola and Guastalla. Eugene’s relationship with the local population has been good and he has kept a tight control: he has executed 48 of his men for looting, telling the Emperor that he had “imposed more severe discipline than has possibly ever been seen in an army.” Eugene receives little cash from the Emperor, far less than he expects, but he secures a sound footing in northern Italy and, as hoped, his success helps to encourage the Maritime Powers to come to the aid of Leopold I. Since the beginning of the year Count Johann Wenzel Wratislaw von Mitrowitz has been in London as Imperial minister, pressing for assistance. With Eugene’s two victories (Carpi and Chiari), Leopold I has proven he would fight to protect his interests, giving Wratislaw the arguments he needs to push through the alliance with the Maritime Powers. On September 7, 1701, within a week of the battle, England and the Dutch Republic sign the second treaty of the Grand Alliance, backing the Emperor’s claims to the Spanish possessions in Italy.

The French are still in Milan, but their position is weak: morale is poor and desertion is high. Louis XIV writes to Villeroy urging him to work closely with Catinat and “not again to attack the enemy without advantage.” “If you do … the King, my grandson, will lose Italy.” By October, French optimism for the campaign is gone, but Louis XIV hopes to send reinforcements for the next year’s campaign, believing the Emperor will not be able to make a comparable increase in Eugene’s strength. However, the campaign season is not yet over. As Villeroy settles down for the winter, Eugene is preparing to attack him at his headquarters in Cremona.