Johan Banér (1596–1641) was a Swedish Field Marshal in the Thirty Years' War. He was a close ally of Gustavus Adolphus, despite the fact that Gustavus's father, Charles IX, had executed Banér's father. Banér entered the army in 1615, and quickly rose through the ranks, serving with distinction in Sweden's wars against Poland and Russia. Banér was present at several critical battles during the Thirty Years' War, including at the Battle of Breitenfeld and the Battle of Alte Veste. He continued the war even after Gustavus's death, with varying degrees of success. He died in 1641.