Former Chief of General Staff Kenan Evren and the then-Commander of Air Forces retired Gen. Tahsin Sahinkaya are the suspects of the case.
Retired General Kenan Evren, symbol of an era when the military dominated Turkish politics, goes on trial on Wednesday for his role leading a 1980 coup that shaped the country for three decades until reforms cut back the power of the "Pashas".
Fifty people were executed, half a million arrested, hundreds died in jail, and many more disappeared in three years of military rule following the Sept. 12, 1980 coup, Turkey's third in 20 years.
More than 30 years later, an Ankara court began hearing the case against 94-year-old Evren, who went on to serve as president, as well as against the other surviving architect of that military takeover, former air force commander Tahsin Sahinkaya, 87.
With the silver-haired Evren now frail, it is unlikely he will appear in court. The prosecutor's office has said it could hear the testimonies of Evren and Sahinkaya via video link. Evren recently underwent intestinal surgery and Turkish media reported on Tuesday that he had also broken an arm.
Evren's trial, unimaginable only a few years ago, will be watched closely by hundreds of military, including top serving and retired commanders, as well as by civilians being tried now as members of the alleged "Ergenekon" and "Sledgehammer" coup conspiracies against Prime Minister Tayyip Erdogan.
For some, the military's constant interventions have stunted the development of a mature political class, while the 1980 coup bequeathed a constitution viewed by many as an additional brake on democratic development.
It was a recent constitutional amendment that ended Evren's immunity from prosecution over the coup.
Evren says he does not regret the coup, arguing it restored order after years of chaos in which 5,000 died in left-right street violence. "Should we feed them in prison for years instead of hanging them?" he said in a speech in 1984, a year after the army handed back rule to a civilian government.
On Tuesday, Erdogan's government, the opposition and parliament joined at least 350 individuals and groups applying to be co-plaintiffs in the trial as aggrieved parties, meaning their grievances will be taken into account during the prosecution and possible sentencing phase.
Prime Minister Tayyip Erdogan said the government had decided it should join the long list of those wronged.
"The first and most important injured party of the coups in Turkey have been the government legitimately representing the nation," Erdogan said in his weekly speech to his parliamentary party On Tuesday. "We will follow the case closely."
The 1980 coup leaders argue they were forced to intervene to restore order after years of chaos.
The country remains haunted by those traumatic times, when virtually the entire political class was rounded up and interned.
Citing the ruling AK Party's spokesman Huseyin Celik, Turkish newspaper Radikal on Tuesday said the authorities were removing the names of key figures in the 1980 and previous military coups from schools, streets, stadiums and military barracks "in a coup house cleaning".
"We need to erase the names of coup plotters from public institutions and from the names of places," Celik said. "They've already been struck from people's hearts."
The September 12, 1980 military coup, headed by Evren, was the third coup in the history of the modern Turkey. The generals seized power in 1980 after years of political unrest, which claimed hundreds of lives. For the next three years Turkish Armed Forces ruled the country through the National Security Council, before democracy was restored.