The battle of Pavia (24 February 1525) was the decisive battle of the First Hapsburg-Valois War, and was a French defeat that saw Francis I captured and that permanently undermined the French position in Italy.
Background and the Pavia Campaign
At the end of his First Invasion of Italy (1515-16) Francis I had secured control of the Duchy of Milan. He had agreed the Treaty of Noyon with the young Charles I of Spain (soon to become the Emperor Charles V), in which Charles acknowledged the French position in Milan and Francis agreed to transfer his claim to Naples through a marriage alliance.
By 1521 this treaty had collapsed. The required marriage was clearly never going to happen, and Francis supported a series of outbreaks of conflict along the Franco-Hapsburg borders. This triggered the First Hapsburg-Valois War (1521-26). Things rarely went well for the French during this war. In 1521 the French were outmanoeuvred in Italy and forced to abandon the city of Milan. A French army under Lautrec attempted to recapture the city in 1522 but was defeated at Bicocca (27 April 1522). In 1523 Charles, duke of Bourbon, defected to the Imperial side after Francis attempted to seize most of his inheritance. A French invasion of Italy late in the year got pinned outside Milan, before in 1524 the French were forced to retreat once again (losing the famous knight Pierre Terrail, seigneur of Bayard during the battle of the Sesia River).
This defeat was followed by an Imperial invasion of Provence. A large Imperial army besieged Marseille (July-August 1524), but the city managed to hold out. When Francis arrived in the south of France at the head of around 40,000 men the Imperial army was forced to retreat back into Italy.
Francis decided to follow up this success with an invasion of Italy. He led his men over the Argentière Pas into the north-west of Italy. The Imperialists were unable to hold onto Milan, where there was an outbreak of plague. They left a garrison in the castle and then retreated to the Alla River, from where they were in communication with Germany and with their Venetian allies. A large garrison was left in Pavia in the hope that it would prevent Francis from attacking Naples.
Francis now had a choice of two options - either besiege Pavia or attack the demoralised Imperial army. He chose to attack Pavia, in the hope that the garrison, under de Leyva, wouldn'd hold out for long. The siege of Pavia began on 28 October and the artillery bombardment in early November, but the defenders turned out to be more determined that Francis had hoped, and the city held out across the winter of 1524-25. During this period Francis did win over Pope Clement VII, who had originally been an Imperial supporter, but Francis then made the mistake of detached 15,000 men under John Stuart, Duke of Albany to invade Naples (to reduce Spanish pressure on the Papal States). These men would be missed during the battle.
While Francis was stuck outside Pavia, Imperial reinforcements were on their way. Georg von Frundsberg brought troops from Germany. Charles de Lannoy, viceroy of Naples, was able to provide some Italian and Spanish troops, despite the threat to Naples. Lannoy was the official commander of the army, but much power was held by Ferdinando Francesco d'Avalos, Marquis of Pescara, who probably came up with the plan of attack for the battle itself.
The city of Pavia sits on the north bank of the Ticino River. In 1525 it was a walled city, contained between the Vernavola stream in the east and the Naviglio stream to the west.
A key feature of the battle was the massive hunting park that extended north from Pavia almost to the village of San Genesio. At the heart of this park was the Castello Mirabello hunting lodge, built for the Sforza dukes of Milan. The Vernavola stream ran through the middle of this park, running just to the east of the hunting lodge. In 1525 the park was surrounded by a strong wall, with eastern and western boundaries running parallel to the stream and a linking wall that run just south of the village. The wall was broken by a number of gates, but it provided a serious obstacle to large scale military manoeuvres.
Other key positions included the Five Abbeys area, where the Vernavola stream flowed out of the south-eastern corner of the hunting lodge on its way around the eastern flank of the city. When Imperial reinforcements arrived the French would fortify this area, giving them a defensive line that linked the Ticino to the Hunting Park wall. About half way up the eastern wall of the park was Torre del Gallo, another key French position.
Build-up to the Battle
On 2 February the Imperial relief army camped close to Casa della Terra, north-east of Pavia, outside the eastern wall of the hunting camp. On the following day Francis began to build fortifications facing away from Pavia and towards the relief army, with key strong points at the Five Abbeys and Torre del Galllo. His main camp was close to the Mirabello hunting lodge, so the French lines ran north from Pavia, facing east towards the relief army.
The two main armies were now divided by the unfordable Vernavola. The Imperialists were able to get some supplies into Pavia, but the relief army was also short of money and food, and so couldn't afford a lengthy standoff.
Francis was also in a difficult position. He lost 6,000 of his Swiss troops (either sent away to secure the lines of communication with Switzerland or simply through desertion, depending on your source). Francis now had roughly the same number of men as the Imperialists, but had the difficult task of having to watch the relief army and continue the blockade of Pavia.
The key moment came on the night of 23-24 February, when Lannoy decided to outflank the French positions. The Imperial artillery began a night bombardment of the French camp, to cover a movement of the main Imperial army to the right (north). The army crossed the stream two miles above the trenches and then moved back south, reaching the wall near San Genesio. Imperial engineers then began to break through the wall, but it took longer than expected, and the Imperial movement wasn't completed by dawn.
The battle itself soon descended into a vast melee, with different sources giving different orders of events. Some aspects of the battle are recorded in most sources. Francis realised that he needed to win time for the rest of his army to draw up and so led a series of cavalry charges on the Imperialists. The discipline of the Spanish harquebusiers meant that in combination with their pike men they were able to defeat the French cavalry attacks. Francis had also left his infantry unsupported, and they began to suffer under Imperial attack.
Further south de Leyva led the garrison of Pavia in an attack on the southern end of the hunting part and the French siege lines. The Swiss held on for some time, but eventually broke and fled towards a bridge over the Ticino. This bridge was broken down during their retreat, and most of the Swiss force was lost.
At the northern end of the camp the battle turned against Francis after about two hours. He continued to lead his cavalry, but eventually his horse was killed under him and he was captured.
About a third of the army escaped under the command of Charles IV, Duke of Alencon, who was later made a scapegoat for the defeat.
Francis was held captive in Italy for a period, before agreeing to move to Madrid, where he hoped to win over Charles V. Instead he was forced to agree to the Treaty of Madrid of 1526 in which he gave up his claims to Naples, Milan, Burgundy, Artois and Flanders. Immediately after being released Francis repudiated the treaty on the grounds that he had been forced to sign it, and the Second Hapsburg-Valois War broke out later in 1526. Francis spent much of the rest of his reign attempting to undo the damage done at Pavia, but he was never really able to restore the French position in Italy.
Quite a few notable French commanders were caught up in the disaster. Amongst the dead were Admiral Bonnivet, Louis II, viscount La Tremoille, Jacques de la Palice, the Duke of Lorraine and the exiled Richard de la Pole (the last serious Yorkist contender to the English throne after the Wars of the Roses). Amongst the captives were Blaise de Lasseran-Massecome, Siegneur of Monluc and Anne de Montmorency, both important commanders later in the war, and Henry II of Navarre (who escaped soon afterwards). Francis's army had been destroyed, and the force sent to Naples under Albany dissolved after the news of the defeat reached them.