The last two surviving leaders of the Khmer Rouge regime have been convicted of genocide by an international tribunal.
The Khmer Rouge was a brutal regime that ruled Cambodia in the 1970s, under the leadership of a dictator Pol Pot.
Nuon Chea, 92, was the deputy of regime leader Pol Pot, and Khieu Samphan, 87, was head of state.
Both men have suggested they were targets of political persecution.
The verdict read aloud in the courtroom by Judge Nil Nonn established the Khmer Rouge committed genocide against the Vietnamese and Cham minorities.
Scholars had debated whether suppression of the Chams, a Muslim ethnic group whose members had put up a small but futile resistance against the Khmer Rouge, amounted to genocide.
The court found Khieu Samphan not guilty of genocide against the Cham, for lack of evidence, though he was found guilty of genocide against the Vietnamese under the principle of joint command responsibility.
The Khmer Rouge sought to achieve an agrarian utopia by emptying the cities to establish vast rural communes. Instead their radical policies led to what has been termed "auto-genocide" through starvation, overwork and execution.
The crimes against humanity convictions covered activities at work camps and cooperatives established by the Khmer Rouge.
These offences comprised of the following:
Persecution on political, religious and racial grounds
Attacks on human dignity
The breaches of the Geneva Convention governing war crimes included wilful killing, torture or inhumane treatment.
Chea was brought by ambulance and Samphan by van from the nearby prison where they are being held.
The prison and the courthouse were custom built for the use of the tribunal, which is officially called the Extraordinary Chambers in the Courts of Cambodia, or ECCC.
Both defendants were present as Judge Nil Nonn opened the proceedings, but Nuon Chea suffers heart problems, so was granted permission to later move from the hearing room to a separate holding room.
Samphan was present for the entire hearing and with the help of two security guards stood as his sentence was read, showing no obvious emotion.
A large crowd of spectators attended Friday’s session, including members of the Cham minority.
Lah Sath, a 72-year-old Cham man from eastern Kampong Cham province, brought his wife and four young granddaughters to Friday’s session.
He said he often heard people talking about the trial and sometimes watched it on TV, but decided it was time to see it with his own eyes.
Just talking about the Khmer Rouge brought back horrible memories of life in those years, he said.
The Cham were treated as enemies and exploited without mercy as they were forced to do intensive farm labour, he recalled.
Lah Sath said his younger brother was killed by Khmer Rouge for failing to take good care of a cow.
The tribunal has also carried out one other prosecution, resulting in the 2010 conviction of Kaing Guek Eav, known as Duch, who as head of the Khmer Rouge prison system ran the infamous Tuol Sleng torture centre in Phnom Penh.
There are fears politics will thwart the tribunal from undertaking any further prosecutions.
Cambodia’s long-serving, autocratic prime minister Hun Sen has declared he will allow no further case to go forward, claiming they would cause instability.
Mr Hun Sen was a Khmer Rouge commander who defected when the group was in power and was installed in government after the Khmer Rouge were ousted from power by a Vietnamese invasion.
"International tribunals are better than the alternative, impunity. They will always be political and fall short of expectations," Alexander Hinton, an anthropology professor at Rutgers University and author of two books about the tribunal, said ahead of Friday’s verdicts.
"But justice is usually delivered, even if at times, as has been the case with the ECCC, it staggers across the finish line."