The former head of Turkey's armed forces, General Ilker Basbug, was in custody on Friday on charges of trying to overthrow the government, a stunning move by the judiciary against a military that was once the ultimate power in the land.
Basbug, who retired in 2010 as chief of NATO's second-largest army, is the most senior officer to be caught up in the Ergenekon case, a long-running crackdown on the military and the secularist establishment.
He was charged overnight and jailed, crowning the fall from grace of the once invincible military. The General Staff chief was Turkey's most powerful man until Prime Minister Tayyip Erdogan's government gradually eroded army influence in the last decade.
Erdogan managed the transformation thanks to overwhelming public support for his government, now in its third term.
Over the past couple of years Turks have become used to the sight of military officers being sent to jail, but the move against a former chief was unprecedented and will stir emotions.
It's a first. It's never happened before, Murat Yetkin, editor of the Hurriyet Daily News, told Reuters. The country has to live through this thing.
Police said they first unearthed evidence five years ago of an ultra-nationalist network dubbed Ergenekon.
Authorities accused it of conspiring to create an atmosphere of chaos that could pave the way for military intervention to unseat the AK Party government because of the Islamist pedigree of its leaders. Erdogan denies that his socially conservative party harbours any religious agenda.
Hundreds of people have been arrested in the Ergenekon investigation, including military officers, academics, lawyers and journalists, though many people are sceptical about the existence of the shadowy network described by prosecutors.
Basbug was taken from an Istanbul courthouse in the early hours of Friday for a health check before being taken in a police convoy to Silivri prison, some 80 km (50 miles) west of the city, where hundreds of defendants in the Ergenekon case are being tried in a specially built courtroom.
The Republic of Turkey's 26th general chief of staff has been remanded in custody for forming and directing a terrorist group. I leave it to the great Turkish nation to judge, Basbug said as he was led from the courtroom.
Turkey's financial markets, hardened to political turmoil, showed no reaction to the news, with the lira and shares firmer.
The wind has been blowing against the military for years, and while Basbug's humiliation was shocking to many people it was part of a well-worn trend.
In a sense it's not surprising, given the evolution of civil military relations over the past decade, but it is a significant moment in the profoundly changed balance of civilian and military power in Turkey, Ian Lesser, of the German Marshall Fund of the United States, told Reuters from Brussels. This development would have been inconceivable a decade ago.
The decision to jail Basbug was taken hours after prominent journalists on trial over alleged ties to the Ergenekon network said the charges against them were a massacre of justice.
Turkey's military, NATO's second-largest army, has long seen itself as the guarantor of the country's secular constitution. It staged three coups between 1960 and 1980 and put pressure on another government to leave power in 1997.
Few Turks believe the military still represents a threat to their democracy as Erdogan has driven the generals decisively out of the political sphere.
In the first government reaction to the court's decision, Deputy Prime Minister Besir Atalay said Basbug's jailing was an important event but played down concern about the impact on government relations with the military.
There is a great normalisation process in Turkey, the point of view is changing, (to) where whoever does something wrong, it is deemed wrong, he said in an interview with CNN Turk.
President Abdullah Gul appealed for calm and stressed the principle of suspects being innocent until proved guilty.
We need to follow this with a cool head, Gul said.
MILITARY PRESTIGE ERODED
Basbug, facing charges of gang leadership and trying to unseat the government by force, told the court after seven hours of questioning by prosecutors that he rejected the charges and described them as tragicomic, broadcaster NTV reported.
To hear such an allegation hurts my pride as a general who has done his duty to the country and state with honour. Accusing a chief of general staff of forming a terrorist group is the biggest punishment I could be given, he was quoted as saying.
The investigation of Basbug centres on allegations that the military set up websites to spread anti-government propaganda to destabilise Turkey.
Ergenekon is seen as part of a power struggle between Erdogan's AK party, which has roots in a banned Islamist party and swept to power in 2002, and the secularist establishment.
Critics accuse the government of scaremongering to silence opponents. The government denies any such motive.
Opposition leaders said the allegations against Basbug were politically motivated and would sow chaos.
Presenting the TSK (Turkish Armed Forces) and its members as a base for setting up terrorist groups will open the way for crisis and chaos that cannot be controlled, said Devlet Bahceli, leader of the right-wing Nationalist Movement Party (MHP).
Kemal Kilicdaroglu, leader of the main opposition Republican People's Party (CHP), said: I have said before that the courts with special authority are not courts which dispense justice but ones which approved the decisions taken by the political authority. I still think that.
The charge of leading a terrorist group is especially painful for an officer who spent his military career fighting the Kurdistan Workers Party (PKK), a militant group designated a terrorist organisation by Turkey, the United States and the EU.
The military is currently under the spotlight over airstrikes on the Iraqi border which killed 35 villagers mistaken for PKK fighters.
Its prestige suffered another blow this week when prosecutors sought life imprisonment for former general staff chief and president Kenan Evren for leading a 1980 coup.
Basbug's lawyer said he would challenge the decision to jail Basbug pending trial, state-run Anatolian news agency reported.
The fact that prosecutors are now touching senior generals is a turning point in the democratisation process of Turkey. Many were sceptical that prosecutors would go this far, said military affairs analyst Lale Kemal.
I would not be surprised if we see some commanders resign but I do not expect this to bring serious instability to Turkey, she said.
Last July, Basbug's successor and the heads of the army, navy and air force resigned in protest against the detention of more than 200 officers in the Sledgehammer case.
(Additional reporting by Simon Cameron-Moore; Writing by Daren Butler and Ibon Villelabeitia)