The battle of La Bicocca (27 April 1522) was the first in a series of French battlefield defeats in Italy during the First Hapsburg-Valois War and saw an army sent to recapture Milan defeated just outside the city.
Francis I of France had secure control of the Duchy of Milan during his first invasion of Italy of 1515-16, but the French position turned out to be rather insecure. Soon after the outbreak of the First Hapsburg-Valois War (1521-26) a combined Spanish, German and Papal army under Prospero Colonna had outmanoeuvred the French under Marshal Odet de Foix, Count of Lautrec, and in November Milan fell to the Allies. Only the castle held out for the French. Francesco Maria Sforza was installed as Duke, and Colonna settled down to besiege the castle. His only serious problem was a financial one, which forced him to reduce the size of his army.
In the spring of 1522 Lautrec returned to Lombardy at the head of a large army. He had around 25,000 men under his direct control (including 8,000 Swiss infantry), and could also call on 10,000 Venetian allies. His main problem was a lack of money, and this would eventually force him to adopt a very offensive strategy.
Lautrec faced an Imperial army of around 20,000 men, still commanded by Colonna, with the Marquis of Pescara serving under him. The Imperial forces had built a series of fortified positions around Milan. The battle would be fought at La Bicocca, a country house a few miles outside Milan. The house was surrounded by a garden wall and ditch, and this had been strengthened with fresh fortifications.
Lautrec's biggest problem was the shortage of money. The Swiss presented him with an ultimatum - either attack immediately or they would go home.
Lautrec decided to attack the Imperial camp. He wanted to begin with an artillery bombardment, but his Swiss infantry was too impatient, and launched an attack in two massive columns, hoping to overwhelm the Imperial defenders with sheer weight of numbers.
This turned into a total disaster - the Swiss were stopped at the Spanish entrenchments, and suffered heavy losses at the hands of the Spanish arquebusiers and artillery. They lost around 3,000 dead in half an hour and barely got to grips with the Spanish. Lautrec attempted to help them by sending his heavy cavalry to attack the rear of the Imperial position, but this attack was repulsed by the Milanese cavalry under Francesco Sforza.
In the aftermath of the defeat Lautrec's army fell apart. Three days after the battle the surviving Swiss left for home, while Lautrec was forced to retreat east into Venetian territory.
The defeat at La Bicocca was the first of three major battlefield defeats suffered by the French in Italy. Late in 1523 a fresh army under Guillaume de Bonnivet invaded Lombardy, but in the following year Bonnivet was forced to retreat. During the retreat his army suffered a defeat at the Sesia (30 April 1524), in which the famous French commander Bayard was killed. After a failed Imperial invasion of the south of France, Francis I led his army back into Lombardy, only to suffer a crushing defeat at Pavia (24 February 1525), effectively ending the war.