OCR Specification focus:
‘Opposing League, reconciliation attempts and leadership, the death of Luther; the Schmalkaldic War (1546–1547): the Battle of Mühlberg (1547), the Augsburg Interim (1548), truces and shifting alliances including Maurice of’
The mid-sixteenth century was a turbulent period in the Holy Roman Empire, as Charles V confronted the challenge of Protestant reform, shifting alliances, and escalating political conflict.
The Opposing League and Attempts at Reconciliation
The Schmalkaldic League
The Schmalkaldic League was a defensive alliance of Protestant princes and cities formed in 1531, primarily to protect Lutheran interests against Charles V. Its membership included leading figures such as Philip of Hesse and John Frederick of Saxony, and it received support from key urban centres.
Schmalkaldic League: A military and political alliance of Protestant princes and cities in the Holy Roman Empire, established to defend their religious and territorial interests against imperial threats.
This organisation strengthened Protestant resistance and complicated Charles V’s attempts to enforce religious conformity within his empire.
Efforts to Negotiate Religious Unity
Charles V, despite his devout Catholicism, repeatedly sought compromise to preserve imperial unity. Notable reconciliation attempts included:
The Augsburg Interim (1548), which attempted to impose a temporary settlement, blending Catholic doctrine with limited concessions to Protestants.
The Regensburg Colloquy (1541), an earlier but ultimately unsuccessful dialogue between Protestant and Catholic theologians.
These measures reflected Charles’s desire to hold together the diverse empire, particularly when preoccupied with foreign wars against France and the Ottoman Empire. However, religious divisions proved too entrenched to reconcile permanently.
The Death of Luther
The death of Martin Luther in 1546 deprived the Protestant movement of its founding figurehead. While his influence persisted through his writings and followers, his absence created a leadership vacuum. This contributed to intensified political tensions, as princes pursued more independent policies without the moderating authority of Luther himself.
The Schmalkaldic War (1546–1547)
Causes of the War
The Schmalkaldic War erupted in 1546 when Charles V, emboldened by temporary peace on his other fronts, turned to confront Protestant defiance directly. Key causes included:
The refusal of Protestant princes to abandon Lutheran reforms.
Charles’s determination to restore Catholic unity in the empire.
The influence of the papacy, which pressured the emperor to act decisively.
The Course of the War
The Schmalkaldic League initially mobilised forces, but internal divisions undermined its strength. Charles secured support from Catholic princes and even gained temporary alliances that shifted the balance in his favour.
Key stages included:
Initial campaigns (1546): Charles launched offensives, exploiting Protestant disunity.
The Battle of Mühlberg (April 1547): A decisive imperial victory where the League’s forces were crushed. Both Philip of Hesse and John Frederick of Saxony were captured, significantly weakening Protestant resistance.
Battle of Mühlberg (1547): A pivotal battle of the Schmalkaldic War in which Charles V decisively defeated the Schmalkaldic League, marking the high point of imperial power over Protestant forces.
This victory gave Charles V temporary dominance, though underlying tensions remained unresolved.
The Augsburg Interim (1548)
Following victory, Charles attempted to enforce religious uniformity through the Augsburg Interim. This decree sought to:
Reinstate key Catholic practices, including the mass and clerical celibacy.
Allow certain concessions, such as clerical marriage and communion in both kinds, to appease Protestants.

Autograph letter by Charles V requiring full enforcement of the Augsburg Interim in Würzburg. It illustrates the emperor’s post-Mühlberg authority and the top-down mechanisms of confessional policy in the Empire. Source
The settlement proved deeply unpopular with both sides. Protestants rejected it as a betrayal of their principles, while Catholics viewed it as too compromising. Its failure illustrated the limits of Charles’s authority and the difficulty of imposing religious unity in practice.
Truces and Shifting Alliances
Maurice of Saxony
One of the most significant shifts was the role of Maurice of Saxony, a Protestant prince who initially aligned with Charles V to secure territorial advantages.
Maurice of Saxony: A Protestant duke who betrayed the Schmalkaldic League by supporting Charles V during the Schmalkaldic War but later turned against the emperor in pursuit of political independence.
Maurice’s eventual betrayal of Charles, forming alliances with Henry II of France, illustrated the fluid and self-serving nature of sixteenth-century German politics.
Ongoing Instability
Even after the imperial victory, religious and political stability remained elusive:
Protestant territories continued to resist Catholic restoration.
Foreign wars forced Charles to negotiate truces rather than consolidate permanent control.
The fragmentation of loyalties in the empire limited the emperor’s ability to impose a lasting settlement.
Legacy of the Schmalkaldic Conflict
The Schmalkaldic War highlighted the interplay of religion and politics within the empire. While Charles achieved a temporary triumph at Mühlberg, the failure of the Augsburg Interim and shifting alliances demonstrated the enduring strength of Protestantism. By the late 1540s, it was clear that imperial authority could not fully suppress the religious diversity of the Holy Roman Empire, setting the stage for continued conflicts and eventual compromise in the Peace of Augsburg (1555).
FAQ
The Papacy, particularly under Pope Paul III, pressured Charles V to act decisively against Protestant princes, fearing the further erosion of Catholic authority in the Empire.
Financial support from the Pope, including subsidies to fund imperial troops, was crucial in enabling Charles to mount a military campaign. However, papal backing came with strings attached, limiting Charles’s ability to negotiate compromises with Protestants.
Geography was a decisive factor. The Schmalkaldic League positioned itself near the River Elbe, believing the river provided strong natural defences.
Charles V’s forces executed a surprise dawn crossing of the river, catching the Protestant army off guard. The element of surprise, enabled by careful use of terrain, played a significant role in the imperial victory.
Maurice of Saxony sought to expand his territorial holdings at the expense of his cousin, John Frederick of Saxony. Supporting Charles V during the Schmalkaldic War enabled him to gain the electoral dignity.
Later, disillusionment with imperial overreach and the unpopular Augsburg Interim prompted Maurice to shift allegiance, allying with France and turning on Charles in 1552.
The Augsburg Interim met widespread opposition among common people as well as elites.
Protestants resented the return of Catholic practices like the mass, which clashed with their religious convictions.
Catholics felt betrayed by concessions such as clerical marriage, which undermined traditional discipline.
In many towns, enforcement proved impossible, leading to unrest and passive resistance from congregations and clergy alike.
The war weakened Protestant unity by removing key leaders such as Philip of Hesse and John Frederick of Saxony from the political stage.
Meanwhile, princes like Maurice of Saxony rose in prominence, showing that loyalty to the emperor could bring significant short-term rewards.
Ultimately, the war revealed the fragility of imperial authority, as princes retained substantial autonomy and often acted out of self-interest rather than religious conviction.
Practice Questions
Question 1 (2 marks)
In which year did the Battle of Mühlberg take place, and why was it significant for Charles V?
Mark scheme:
1 mark for correct year: 1547.
1 mark for correct significance: e.g. decisive victory over the Schmalkaldic League, capture of Philip of Hesse and John Frederick of Saxony, or demonstration of Charles’s temporary dominance.
Question 2 (6 marks)
Explain two reasons why the Augsburg Interim (1548) failed to provide a lasting religious settlement in the Holy Roman Empire.
Mark scheme:
Up to 3 marks per reason, awarded as follows:
1 mark for identifying a valid reason.
1 mark for explaining the reason.
1 mark for developing the explanation with context or detail.
Examples include:
Protestants rejected the Interim as a betrayal of their beliefs (1); because it reinstated Catholic practices such as the mass (1); which they viewed as unacceptable after years of reform (1).
Catholics opposed the Interim as too compromising (1); since it allowed limited concessions like clerical marriage (1); weakening Charles’s credibility among Catholic supporters (1).
Charles lacked the political and military resources to enforce the Interim uniformly (1); because of distractions from foreign wars (1); meaning enforcement was inconsistent across the Empire (1).
Maximum 6 marks.