Battle of Mühlberg

On 24 April 1547, beside the River Elbe near the Saxon town of Mühlberg, the emperor Charles V surprised and routed the army of John Frederick I, Elector of Saxony, the leading Lutheran prince of the Schmalkaldic League. The elector was captured and the league broke up. Yet the religious question was not settled, and eight years later the Peace of Augsburg gave Lutheranism legal recognition in the empire.

The Protestant Reformation that began in 1517 gave many German princes and cities a way to assert their independence from the emperor in politics as well as religion. In 1531, opposing Charles's attempt to enforce the condemnation of Lutheranism, Protestant rulers led by John Frederick of Saxony and Philip of Hesse formed a defensive alliance named after the Thuringian town of Schmalkalden. Free cities and, at times, France supported it. For years Charles, who needed German help against the Ottomans, tolerated the league.

That changed in the mid-1540s. The Treaty of Crépy in 1544 ended his wars with Francis I of France and cut the league off from French support, and Martin Luther died in 1546. The opening came from a family quarrel within the House of Wettin: John Frederick's Protestant cousin Maurice, who had refused to join the league, invaded the elector's lands in 1546 with the help of Charles's brother Ferdinand. John Frederick drove him out, but in 1547 Charles entered the war in force, subdued Württemberg and the Palatinate and marched on Saxony.

The elector had divided his forces, sending a large part to Bohemia in the hope of sparking a rising there, and was retreating north towards his fortress of Wittenberg. He camped at Mühlberg, trusting the broad Elbe to protect him and leaving only a few guards on the bank. Charles, suffering from gout, reached the river on the evening of 23 April and, against the advice of his generals, decided to attack.

At dawn, under cover of thick fog, Spanish and Italian veterans swam across and overcame the Saxon pickets. Following a plan of the Duke of Alba, the emperor's commander, troops found a ford with the help of a local farmer, while others stopped the Saxons from destroying a pontoon bridge, which the imperial cavalry then used. One story claims that John Frederick was at Mass and could hardly believe an attack was under way.

The elector, thinking he faced only an advance guard, formed up along the edge of a forest. Charles was carried to the field in a litter; Titian's famous equestrian portrait of 1548 shows him instead in armour on horseback. The imperial army, perhaps 16,000 to 20,000 strong, outnumbered the Saxons, whose ranks were filled largely with peasants. The Saxons repulsed the opening charges by Hungarian horsemen, but once Alba and Maurice had broken the flanks, the Spanish and Italian tercios shattered the centre. The fleeing army was hunted down in the forest. John Frederick was wounded in the face and taken prisoner.

Saxon losses are estimated at 2,000 to 3,000 men in some accounts and as high as 8,000 in others, with almost all their artillery taken; the imperial side lost about fifty. Charles is said to have adapted Caesar's famous words: "I came, I saw, and God conquered."

Charles spared John Frederick's life in exchange for the surrender of Wittenberg, but kept him prisoner until 1552 and transferred the electoral title to Maurice. Philip of Hesse surrendered soon afterwards, ending the war. The emperor's interim religious settlement of 1548 failed to reconcile the two sides, and several Protestant reformers, Martin Bucer among them, took refuge in England. In 1555 the Peace of Augsburg allowed each ruler in the Holy Roman Empire to choose between Catholicism and Lutheranism.

Our 1530 map shows the Holy Roman Empire and the Saxon lands in eastern Germany on the eve of the Schmalkaldic War, and the 1600 map shows the empire after the Augsburg settlement.