The War of the League of Cognac (1526–30) was fought between the Habsburg dominions of Charles V—primarily the Holy Roman Empire and Spain—and the League of Cognac, an alliance including the Kingdom of France, Pope Clement VII, the Republic of Venice, the Kingdom of England, the Duchy of Milan, and the Republic of Florence. Prelude Shocked by the defeat of the Kingdom of France in the Italian War of 1521, Pope Clement VII, together with the Republic of Venice, began to organize an alliance to drive Charles V from the Italian Peninsula. Francis I, having signed the Treaty of Madrid, was released from his captivity in Madrid and returned to France, where he quickly announced his intention to assist Clement. Thus, on 22 May 1526, the League of Cognac was signed by Francis, Clement, Venice, Florence, and the Sforza of Milan, who desired to throw off the Imperial hegemony over them. Henry VIII of England, thwarted in his requests to have the treaty signed in England, refused to join. Initial moves The League quickly seized Lodi, but Imperial troops marched into Lombardy and soon forced Sforza to abandon Milan. The Colonna, meanwhile, organized an attack on Rome, defeating the Papal forces and briefly seizing control of the city in September 1526; they were soon paid off and departed, however. Rome Charles V now gathered a force of 14,000 German landsknechts and 6,000 Spanish tercios led by Georg Frundsberg and Charles of Bourbon; the forces combined at Piacenza and advanced on Rome. Francesco Guicciardini, now in command of the Papal armies, proved unable to resist them; and when the Duke of Bourbon was killed, the underpaid armies sacked the city, forcing the Pope to take refuge at Castel Sant'Angelo. His escape was made possible by the Swiss Guards' last stand. Naples The looting of Rome, and the consequent removal of Clement from any real role in the war, prompted frantic action on the part of the French. On 30 April 1527, Henry VIII and Francis signed the Treaty of Westminster, pledging to combine their forces against Charles. Francis, having finally drawn Henry VIII into the League, sent an army under Odet de Foix and Pedro Navarro, Count of Oliveto through Genoa—where Andrea Doria had quickly joined the French and seized much of the Genoese fleet—to Naples, where it proceeded to dig itself in for an extended siege. Genoa Doria, however, soon