William IV, Duke of Bavaria

3.1. Co-regency and Early Rule

Despite his father, Albert IV, having established the principle of primogeniture in 1506, ensuring the succession of the firstborn prince, William's younger brother, Louis, challenged this decree. Louis argued that he was born before the edict officially came into effect, thus asserting his right to co-rule. With the strong backing of their mother, Kunigunde, and the States-General, Louis successfully compelled William to accept him as a co-regent. This arrangement began in 1516, with Louis primarily governing the districts of Landshut and Straubing. Despite the initial dispute, the brothers generally ruled in concord until Louis X's death in 1545, after which William ruled Bavaria alone.

3.2. Religious Policies and the Counter-Reformation

Initially, William IV showed some sympathy towards the burgeoning Protestant Reformation. However, as the movement gained significant popularity and influence across Bavaria, his stance shifted dramatically. In 1522, he issued the first Bavarian religion mandate, a decree that explicitly prohibited the dissemination and promulgation of Martin Luther's works within his duchy. Following an agreement with Pope Clement VII in 1524, William solidified his position as a staunch defender of Catholicism and emerged as a prominent political leader of the German Counter-Reformation. This commitment to the Catholic cause, however, did not prevent him from maintaining an opposition to the powerful House of Habsburg, particularly due to his brother Louis X's claim to the Bohemian Crown. His policies, while strengthening the Catholic Church, also led to the suppression of dissenting religious views, impacting the religious freedom of his subjects.

3.3. Conflicts and Diplomacy

William IV played a critical role in the political and social upheavals of his time. In 1525, he, alongside his brother Louis X, formed an alliance with the Archbishop of Salzburg to brutally suppress the German Peasants' War in South Germany. This peasant uprising, driven by economic hardship and religious grievances, was met with severe force, resulting in widespread casualties and a reinforcement of existing social hierarchies. While effectively quelling the rebellion, William's actions contributed to the suffering of the common people and solidified the power of the nobility.

The long-standing conflict between the Wittelsbach dukes and the Habsburgs concluded in 1534. William and Louis X reached an agreement with Ferdinand I in Linz, resolving their dynastic disputes. Subsequently, William IV aligned himself with Emperor Charles V, supporting him in the Schmalkaldic War against the Protestant Schmalkaldic League in 1546. Despite his support, he was ultimately unsuccessful in his efforts to preserve the Palatine electoral dignity. Throughout 35 years of his reign, William's powerful chancellor was Leonhard von Eck, a key figure in implementing his policies.

4.1. Reinheitsgebot

One of William IV's most famous and enduring contributions was the proclamation of the Reinheitsgebot, or "purity regulation," for beer brewing. This historic decree was issued on 23 April 1516, before a committee of gentry and knights in Ingolstadt. The law stipulated that only three ingredients-barley, hops, and water-could be used in the brewing of Bavarian beer. This regulation aimed to ensure the quality and purity of beer, which was a staple drink and an important economic product. The Reinheitsgebot remained a legally binding obligation in Bavaria for centuries, shaping the region's brewing traditions and becoming a cornerstone of Bavarian identity. It was only officially abolished as a binding obligation in 1986 due to Paneuropean regulations introduced by the European Union, though its principles continue to influence German brewing.

4.2. Patronage of Arts and Architecture

William IV was a significant patron and commissioner of art, contributing to the flourishing of the arts in Bavaria. In 1523, his appointment of the renowned composer Ludwig Senfl marked the beginning of the ascent of the Bavarian State Orchestra. He was also an avid collector, amassing an important suite of paintings from various artists. Among his most notable commissions was The Battle of Issus by Albrecht Altdorfer, a masterpiece of the Danube School. This painting, along with much of William's extensive collection, is now housed in the Alte Pinakothek in Munich.

His architectural endeavors were equally impactful. William ordered the expansion of the Neuveste, a part of the Munich Residenz, with the construction of the Rundstubenbau. This project, along with the establishment of the first Court Garden, marked the beginning of the Munich Residenz's transformation into a grand, representative palace. Altdorfer's painting was part of a history cycle intended for a garden pavilion within this complex. In 1546, William and his son Albert V initiated the transformation of Dachau Palace. Originally a Gothic ruin, it was rebuilt into a four-winged palace in the Renaissance style, complete with a court garden. This redesigned palace later became a favored residence for the rulers of Bavaria.

4.3. Eckbibel and Linguistic Contributions

Another significant cultural contribution during William IV's reign was the commissioning of the Eckbibel. This biblical translation, completed in 1537, was undertaken by Johann Eck on behalf of William. Theologically, the Eckbibel was a direct counter to Martin Luther's German Bible translation, serving as a key text among the Catholic "correction bibles" of the Counter-Reformation. Beyond its religious significance, the Eckbibel holds considerable importance in the field of linguistics. Unlike many contemporary texts that were written in the East German Saxon dialect, the Eckbibel was composed in the Bavarian Upper German dialect, thereby contributing to the standardization and recognition of this regional language variant.

5.1. Marriage and Offspring

In 1522, William IV married Jakobaea of Baden (1507-1580). She was the daughter of Margrave Philip I of Baden and his consort Princess Elisabeth of Palatinate. Together, William and Jakobaea had four legitimate children:

• Theodor of Bavaria (10 February 1526 - 8 July 1534)
• Duke Albert V of Bavaria (1528-1579), who would succeed his father as Duke
• Wilhelm of Bavaria (17 February 1529 - 22 October 1530)
• Mechthild of Bavaria (12 July 1532 - 2 November 1565), who married Philibert of Baden (1536-1569) in 1557.

In addition to his legitimate children, William IV also had two known illegitimate children:

• Knight Georg von Hegnenberg (circa 1509-1590), who later married Margarete Hausner von Stettberg.
• Anna (died 1570), whose mother is not recorded.

8.1. Positive Contributions

Among William IV's most notable positive contributions is the Reinheitsgebot of 1516, which not only standardized beer brewing but also became a symbol of Bavarian identity and a foundation for its renowned brewing industry. His extensive patronage of arts and architecture fostered a vibrant cultural environment. Commissions like Albrecht Altdorfer's Battle of Issus and the expansion of the Munich Residenz and Dachau Palace enriched Bavaria's artistic heritage and architectural landscape. Furthermore, his support for the Eckbibel contributed to the development and recognition of the Bavarian Upper German dialect, demonstrating a commitment to regional linguistic identity even within the context of religious counter-reform. These actions collectively solidified Bavaria's cultural distinctiveness and artistic reputation.

8.2. Criticisms and Controversies

Despite his cultural achievements, William IV's political actions drew criticism, particularly his role in the suppression of the German Peasants' War in 1525. His decision to ally with the Archbishop of Salzburg and violently quell the peasant uprising, driven by their demands for social justice and religious freedom, highlights a conservative approach that prioritized maintaining the existing power structure over addressing the grievances of the populace. This suppression resulted in significant loss of life and reinforced the oppressive conditions for many common people.

Furthermore, his shift from initial sympathy towards the Reformation to becoming a leading figure in the German Counter-Reformation involved the banning of Martin Luther's works and a firm suppression of Protestant ideas. While this strengthened the Catholic Church in Bavaria, it also curtailed religious freedom and intellectual discourse, reflecting the rigid religious climate of the era. His political maneuvering, such as his opposition to the Habsburgs and his failure to preserve the Palatine electoral dignity, also underscore the complexities and challenges of his reign in the volatile political landscape of 16th-century Europe.