Duke John III was a notable figure in the history of the Duchy of Brabant, which is located in present-day Belgium. He was born in 1300 and became Duke in 1312, ruling until his death in 1355. His reign was marked by efforts to strengthen the duchy's economy and political influence in the region. John III was also known for his involvement in the Hundred Years' War, a series of conflicts between England and France. He played a role in various alliances and treaties, aiming to secure peace and stability for his duchy during a tumultuous period in European history.