In the winter of 1701-1702, Maréchal Villeroi’s French army in northern Italy went into winter quarters after an indecisive campaign. Headquarters were situated at the fortified town of Cremona, at the junction of the Adda and Po rivers. Included in the garrison were the Régiment de Dillon and another Irish corps, the Régiment de Bourke. Prince Eugene of Savoy, commanding the allied forces in Italy and an altogether more active commander than Villeroi, sought to gain an advantage over the French prior to the opening of the new year’s campaign, by attempting to seize Cremona by a surprise attack. On the night of January 31st 1702, an Austrian spy inside the city admitted a party of grenadiers by means of a hidden culvert. These then overpowered the guards of the St Margaret Gate, allowing 800 cuirassiers to charge through followed by 4,000 infantry led by Prince Eugene in person. The French garrison troops were cut down as they emerged from their barracks, and Maréchal Villeroi captured in his quarters.
Meanwhile a second Austrian column attempted to storm the Po Gate, which was held by a detachment of 35 men from the Régiment de Dillon. Barricading the windows, this detachment held off the Austrians long enough for the main body of the Irish, commanded by Major O’Mahoney of the Régiment de Dillon, to arrive. The men of Dillon’s and Bourke’s then utterly repulsed the Austrian attack, clearing the enemy infantry from the walls and driving them back onto their cavalry supports so that the whole body dissolved in confusion.
Prince Eugene now sent an Irish officer in the Austrian service to persuade his countrymen to surrender, threatening them with death if they continued to resist. O’Mahoney promptly had the emissary taken prisoner, and then led his men against the main body of the Austrians.
Joined by the rallied survivors of the French garrison, the men of the two Irish regiments cleared the attackers out of the streets. By this time a French relief force was in the offing, and Prince Eugene called off his attack. The Austrians had taken over 2,000 casualties, whilst the French had lost 1,100. Of the latter, 350 were Irish, out of 600 engaged, and 200 of these were from the Régiment de Dillon. O’Mahoney was presented to Louis XIV to make his report in person, and knighted by James III.