When Vladislas' only son Louis was killed at the Battle of Mohács in 1526 ending the Jagiellon dynasty rule in Bohemia, a convention of Bohemian nobles elected his brother-in-law, the Habsburg archduke Ferdinand I of Austria, as the new king of the Bohemian crown lands. Together with the Archduchy of Austria "hereditary lands" and the Hungarian kingdom, they formed the Habsburg Monarchy, which in the following centuries grew out of the Holy Roman Empire into a separate European power. Attempts by the Bohemian Protestant Reformation estates to build up an autonomous confederation were dashed at the 1620 Battle of White Mountain, whereafter the administration was centralised at Vienna. Moreover, the Habsburg rulers lost the Lusatias to the Electorate of Saxony after the Thirty Years' War in the 1635 Peace of Prague, and also most of Silesia with Kladsko to the Kingdom of Prussia after the First Silesian War in the 1742 Treaty of Breslau.