Maximilian I (17 April 1573 – 27 September 1651), occasionally called the Great, a member of the House of Wittelsbach, ruled as Duke of Bavaria from 1597. His reign was marked by the Thirty Years' War during which he obtained the title of a prince-elector of the Holy Roman Empire at the 1623 Diet of Regensburg.
Maximilian was a capable monarch who, by overcoming the feudal rights of the local estates (Landstände), laid the foundations for absolutist rule in Bavaria. A devout Catholic, he was one of the leading proponents of the Counter-Reformation and founder of the Catholic League of Imperial Princes.