Ferdinand III (July 13, 1608 – April 2, 1657) was Holy Roman Emperor from 1637 – 1657. He was also King of Hungary (1625), King of Bohemia (1627), Archduke of Austria (1621), and King of the Romans (Germany) (1636). He served as titular head of the Imperial Army during the Thirty Years' War from 1634 until its final phases.