Wikipedia
The House of Windisch-Graetz, also spelled Windisch-Grätz, was a princely family in the Austrian Empire, serving the Habsburg dynasty.
The name derives from the town of Windischgrätz in the Duchy of Styria, which is today Slovenj Gradec in the Carinthia region of Slovenia. According to the Almanach de Gotha, the family was first recorded in 1242.
Alfred Candidus Ferdinand zu Windisch-Graetz was elevated to the rank of Imperial Prince in 1804. The Holy Roman Empire having been abolished, he and his brother Veriand were both created Princes of the Austrian Empire in 1822, Alfred and his successors being the first line of Princes of Windisch-Graetz and Veriand and his successors the second line.
Great Britain's Princess Michael of Kent is descended from this family through her maternal grandmother, while her husband, Prince Michael of Kent, is a first cousin once removed of Archduchess Sophie Franziska of Austria, Princess of Windisch-Graetz.