An Athens court has found 15 people guilty of involvement in a series of murders and robberies carried out by the Greek radical group November 17.
Savas Xiros (Left) and Dimitris Koufodinas were both convicted
After a nine-month trial, leading members were found guilty on multiple charges relating to crimes dating back from June 2000 to December 1975.
Their victims included Greek and foreign figures, including UK defence attache Brigadier Stephen Saunders.
The convicted men are due to be sentenced on Wednesday.
Relatives of victims, prosecutors and the Greek Government welcomed the outcome of the country's first terrorism trial.
Government spokesman Christos Protopapas, looking ahead to the 2004 Athens Olympics, said: "Terrorism received a decisive blow and of course Greece is now viewed throughout the world as one of the safest countries, something very significant especially in light of the Olympic Games."
Heather Saunders, whose husband was shot dead as he drove to work in Athens in June 2000, said it was the verdict her family "had hoped for".
"They killed 23 people," she told the BBC. "But it is 23 widows, there's
goodness knows how many children, how many parents; they will all carry this scar for the rest of their lives."
Athens Mayor and Olympic Games host Dora Bakoyianni, whose parliamentarian
husband Pavlos Bakoyiannis was shot dead by the group in 1989, said: "Greek justice spoke today. Its decisions are respected by all."
A 20-year statute of limitations in Greek law means that group members will not be sentenced for the first four killings by November 17 - including that of CIA station chief Richard Welch, whose 1975 assassination marked the group's first appearance.
Sentences to follow
The man considered to be the group's leader, Alexandros Giotopoulos, 59, was found guilty of membership of the group and of planning and authorising all their actions.
Giotopoulos, who denied links to the group, said: "The decision was expected. I was condemned from the start."
Dimitris Koufodinas, whom prosecutors argued was the group's main hitman, was also found guilty of membership of the group.
Giotopoulos said the guilty verdict was 'unfounded'
The three judges, who heard the cases without a jury, took 90 minutes to read through hundreds of charges against the 18 men and one woman on trial.
Four of the accused, including the only female defendant, Angeliki Sotiropoulou, were acquitted for lack of evidence.
The ringleaders are expected to receive multiple life terms when they are sentenced on Wednesday.
The court had to reach a verdict within 18 months of the suspects' detention in prison, and that deadline was due to run out in January.
There was no jury because terrorism charges were involved.
Greek police made little progress in their search for the group until last year, when they caught one of the accused apparently trying to plant a bomb.
He informed police of the names and whereabouts of other November 17 members.
Within weeks, police made a series of dramatic arrests.
Giotopoulos, who was charged with direct involvement in 10 attacks, could face 19 life sentences for murder.
The BBC's Tabitha Morgan in Athens says the Greek Government is keen to show the international community that Greece is capable of eliminating terrorist groups ahead of next summer's Olympic Games in Athens.
It will also hope to make political capital out of the successful conclusion of the case ahead of general elections early next year.
November 17 took its name from the date of the crushing of a student uprising in 1973 during Greece's 1967 to 1974 military rule. The radical leftists' attacks were aimed at overthrowing capitalism and attacked US targets because of Washington's support for the junta.
Brigadier Saunders' murder was the last carried out by the group.