Reichsfürst
The House of Windisch-Graetz, also spelled Windisch-Grätz, is an Austrian-Slovenian aristocratic family, descending from Windischgraz in Lower Styria (present-day Slovenj Gradec, Slovenia). The noble dynasty serving the House of Habsburg achieved the rank of "Freiherren" in 1551, of Imperial Counts in 1682 and of Princes of the Holy Roman Empire in 1804. The family belongs to high nobility.