Rudolf of Rheinfelden

Rudolf of Rheinfelden (c. 1025 – 15 October 1080) is Duke of Swabia (1057–1079) and brother-in-law of King Henry IV of Germany.

In 1077, upon the outbreak of the Investiture Controversy, Duke Rudolf is elected alternative king or German antiking by the politically oriented anti-Henry German aristocrats, whose rebellion becomes known as the Great Saxon Revolt.

In the struggle for supremacy in the Holy Roman Empire, he dies as a result of battlefield injuries as his faction meets Henry's forces and defeats them in the Battle of Elster.