Why was Bavaria divided into separate duchies during the Middle Ages?

During the Middle Ages, Bavaria was divided into separate duchies primarily due to the persistent Germanic custom of partitioning ancestral territories among a ruler's sons rather than transmitting the land intact to a single heir.1

While the Wittelsbach dynasty ruled Bavaria from 1180 until 1918, their efforts to consolidate power were frequently undermined by these internal divisions. By the late 14th century, these inheritance practices had fractured the Bavarian lands into multiple duchies, which weakened the central authority of the dukes and allowed local assemblies, such as the Landtag, to gain significant control over government and finances.23

This trend of fragmentation was common among secular potentates throughout Germany during this period, as they often prioritized family inheritance over the integrity of their principalities. The division of Bavaria into branches—such as Ingolstadt, Munich, and Landshut—persisted until the early 16th century, when Duke Albert IV established the rule of primogeniture in 1506 to ensure the territory would remain unified under a single successor.123