The battle opened with several hours of skirmishing between opposing bands of arquebusiers and an ineffectual artillery exchange, after which d'Avalos ordered a general advance.

Known among military historians chiefly for the "great slaughter" that occurred when columns of intermingled arquebusiers and pikemen met in the center, it also demonstrates the continuing role of traditional heavy cavalry on a battlefield largely dominated by the emerging pike and shot infantry.

Boutières seized San Germano Vercellese, near Vercelli, and laid siege to Ivrea; d'Avalos, meanwhile, captured Carignano, only fifteen miles south of Turin, and proceeded to garrison and fortify it.

[5] Francis also sent additional troops to the Piedmont, including several hundred heavy cavalry, some companies of French infantry from Dauphiné and Languedoc, and a force of quasi-Swiss from Gruyères.

[8] Montluc apparently convinced Francis to give his assent—contingent on the agreement of Enghien's captains—over the objections of the Comte de Saint-Pol, who complained that a defeat would leave France exposed to an invasion by d'Avalos's troops at a time when Charles V and Henry VIII of England were expected to attack Picardy.

[10] D'Avalos, having waited for the arrival of a large body of landsknechts dispatched by Holy Roman Emperor Charles V, set off from Asti towards Carignano.

[15] Enghien's officers urged him to attack immediately, but he was determined to fight on ground of his own choosing; on the morning of 14 April, the French marched from Carmagnola to a position some three miles (5 km) to the southeast and awaited d'Avalos's arrival.

[23] The center of the French line was formed by thirteen companies of veteran Swiss, numbering about 4,000, under the joint command of William Frülich of Soleure and a captain named St.

[28] On the far left, facing Des Thermes, were 300 Florentine light cavalry under Rodolfo Baglioni; flanking them to the right were 6,000 Italian infantry under Ferrante Sanseverino, Prince of Salerno.

[34] The skirmishing between the arquebusiers continued for almost four hours; Martin Du Bellay, observing the engagement, described it as "a pretty sight for anyone who was in a safe place and unemployed, for they played off on each other all the ruses and stratagems of petty war.

[30] The Italian formation held, and Des Thermes himself was wounded and captured; but by the time Sanseverino had dealt with the resulting disorder and was ready to advance again, the fight in the center had already been decided.

[40] Madruzzo responded by splitting his column into two separate portions, one of which moved to intercept the French while the other continued up the slope towards the Swiss waiting at the crest.

[46] Both masses of infantry remained locked in a push of pike until the squadron of heavy cavalry under Boutières charged into the landsknechts' flank, shattering their formation and driving them down the slope.

[47] The Imperial heavy cavalry, which had been on the landsknechts' right, and which had been ordered by d'Avalos to attack the Swiss, recoiled from the pikes and fled to the rear, leaving Carlo Gonzaga to be taken prisoner.

[49] Most of the landsknechts' officers were killed; and while contemporary accounts probably exaggerate the numbers of the dead, it is clear that the German infantry had ceased to exist as a fighting force.

Dampierre's cavalry routed Lannoy's company of light horse; the Italians and the contingent from Gruyères, meanwhile, broke and fled—leaving their officers to be killed—without offering any real resistance to the advancing Imperial infantry.

[52] As Cardona's infantry moved past the original French line, Enghien descended on it with the entire body of heavy cavalry under his command; the subsequent engagement took place on the reverse slope of the ridge, out of sight of the rest of the battlefield.

[54] As Cardona's ranks closed again, the French cavalry turned and made a second charge under heavy arquebus fire; this was far more costly, and again failed to break the Imperial column.

[55] Enghien, now joined by Dampierre's light cavalry, made a third charge, which again failed to achieve a decisive result; fewer than a hundred of the French gendarmes remained afterwards.

[56] Enghien believed the battle to be lost—according to Montluc, he intended to stab himself, "which ancient Romans might do, but not good Christians"—when St. Julian, the Swiss commander, arrived from the center of the battlefield and reported that the Imperial forces there had been routed.

[58] Enghien followed closely with the remainder of his cavalry; he was soon reinforced by a company of Italian mounted arquebusiers, which had been stationed at Racconigi and had started towards the battlefield after hearing the initial artillery exchange.

[65] A large number of officers were killed, particularly among the landsknechts; many of those who survived were taken prisoner, including Ramón de Cardona, Carlo Gonzaga, and Eriprando Madruzzo.