The Great Saxon Revolt was a civil war between 1077 and 1088 early in the history of the Holy Roman Empire led by a group of opportunistic German princes who elected as their figurehead the duke of Swabia and anti-king Rudolf of Rheinfeld, a two-way brother-in-law of the young Henry IV, Holy Roman Emperor (Henry was crowned at the age of six and took on his offices when aged sixteen). It followed the Saxon Rebellion of 1073–75.