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A judicial officer waits for the beginning of a landmark trial on April 29, in Stuttgart, Germany. Nine men are accused of a far-right plot to depose the country's goverment.
CNN  — 

Nine suspected members of a German far-right group accused of plotting to overthrow the government and install a minor royal as leader went on trial at a high-security courtroom in Stuttgart on Monday.

Prosecutors opened their case against individuals tied to the Reichsbürger (Citizens of the Reich) movement. In all, 27 people face charges, including high treason and belonging to a terror organization, but they will be tried in three separate courtrooms in different cities.

The plot to overthrow the government and install martial law was exposed in 2022. The nine defendants in court on Monday — including former soldiers and judges, as well as a member of parliament for the far-right Alternative for Germany (AfD) — are accused of participating in the “military arm” of the Reichsbürger, which espouses conspiracy-based theories regarding sovereignty and rejects the concept of the post-war German state.

The men put on a defiant air on the first day of the trial, smiling and talking amongst themselves, according to CNN affiliate NTV. Adding drama, the Stuttgart trial is being held in the Stammheim prison, notorious for the imprisonment of far-left Red Army Faction terrorists in the 1970s.

The three trials together, across Stuttgart, Frankfurt and Munich, account for one of the biggest anti-terror cases in Germany’s modern history.

‘Conglomerate of conspiracy myths’

Businessman Heinrich XIII Prince Reuss, 72, allegedly led the plot. The defendants were believed to have planned the resurrection of the German Reich through violence, storming the German Bundestag — the national parliament — and kidnapping the country’s president, Frank-Walter Steinmeier.

Heinrich XIII Prince Reuss is a descendant of the House of Reuss, the former ruling family of parts of eastern Germany. He allegedly wanted to raid the German parliament and become the head of state.

“The aim of the organization was to violently eliminate the existing state order in Germany and replace it with its own form of government, the main features of which had already been worked out,” the Stuttgart Higher Regional Court said in a statement before the trial.

“The members of the group were united by a deep rejection of state institutions and the free democratic basic order,“ the court said, adding that the defendants had followed a “conglomerate of conspiracy myths.“

Those accused knew the “violent takeover would have involved killing people,” the statement said.

In December, Germany’s Federal Public Prosecutor General issued an indictment against the defendants, saying they “are accused of belonging to a terrorist organization founded at the end of July 2021.”

All of the defendants are charged with participating in a terrorist organization and preparing a highly treasonous enterprise, according to the court.

Two of the defendants are accused of violating the Weapons and War Weapons Control Act. “One of these two defendants is also accused of attempted murder, dangerous bodily harm, resisting and assaulting law enforcement officers,“ according to the court.

CNN’s Nadine Schmidt and Sophie Tanno contributed reporting.