Heinrich XIII Prince Reuss is one of the last descendants of a dynasty that once ruled over swaths of eastern Germany. He is suspected of hoping to become the country's new leader in a violent coup to overthrow the democratic order.
The 71-year-old was one of 25 members and supporters of a far-right group planning the alleged putsch who were arrested early on Wednesday in nationwide raids, according to the authorities.
The real estate developer has for years publicly advocated the theory that life was better worldwide under monarchy. He stems from House of Reuss, which for centuries ruled over parts of present-day Thueringen state until Germany's 1918 revolution that led to the establishment of the Weimar Republic.