Duke Eric of Södermanland was a Swedish nobleman born in 1339. He was the son of King Magnus IV of Sweden and Blanche of Namur. Eric held the title of Duke and governed the region of Södermanland, which is located in central Sweden. His role was significant in the feudal system, where dukes managed lands and supported the king. Eric's life was marked by political challenges, including conflicts with rival factions. He was involved in the power struggles of the time, which were common in medieval Sweden. Eric's legacy is tied to the broader history of the Swedish monarchy and its noble families.