Twenty-five people have been arrested in raids across Germany on suspicion of plotting to overthrow the government.
The group of far-right and ex-military figures is said to have prepared to storm the parliament building, the Reichstag, and seize power.
A minor aristocrat described as Prince Heinrich XIII, 71, is alleged to have been central to their plans.
According to federal prosecutors, he is one of two alleged ringleaders among those arrested across 11 German states.
The plotters are said to include members of the extremist Reichsbürger [Citizens of the Reich] movement, which has long been in the sights of German police over violent attacks and racist conspiracy theories. They also refuse to recognise the modern German state.
Other suspects came from the QAnon movement who believe their country is in the hands of a “deep state”.
An estimated 50 men and women are alleged to have been part of the group, said to have plotted to overthrow the republic and replace it with a new state modelled on the Germany of 1871 – an empire called the Second Reich.
“We don’t yet have a name for this group,” said a spokeswoman for the federal prosecutor’s office.
Three thousand officers took part in 130 raids across much of the country, with two people arrested in Austria and Italy. Those detained were due to be questioned later in the day.