Abdullah Ocalan is seen by Kurdish nationalists as a freedom fighter but by Ankara as a terrorist whose hands are stained with blood.
Ocalan was one of seven children born into a poor farming family in a village on the Syrian border. Ocalan - which means "he who takes revenge" in Turkish - described a ban on the Kurdish language as increasing "the dimensions of oppression" on the Kurdish people.
"I was born with this language. One can call himself a nothing if he can't speak his own language," he once said. But Ocalan reportedly knows little Kurdish and speaks fluent Turkish without a Kurdish accent. He reportedly wanted to be an officer in the Turkish army but failed his entrance examination to military school. Later, the dropout from the political science department at Ankara University became a left-wing militant.
After seven months in a military prison for distributing a leftwing magazine in 1972, Ocalan engaged in clandestine activities to set up a group that would fight for an independent Kurdish state. In 1978, he formed the Kurdistan Workers' Party (PKK) with fellow students. The PKK has since waged an armed battle for the creation of a "Greater Kurdistan".
Around 11 million Kurds live in Turkey, mostly in the south-east, with four million in Iraq, 5.5 million in Iran and one million in Syria. A further 500,000 live in the Caucasus region of the former Soviet Union.
Following a police crackdown on his militants in 1979, he fled to Syria before the Turkish military coup of 1980. Since then, he has lived in exile, most often in Damascus or in the Syrian-controlled part of Lebanon, where he set up his headquarters. On August 15th, 1984, "Apo" launched his armed struggle against Ankara. The PKK staged its first attacks in south-east Turkey, killing two soldiers.
While he led the movement he scolded his senior rebels like children. Those who dared to challenge his authority were sentenced to death, including his wife, condemned for joining Ocalan's opponents, who accused him of using dictatorial policies. "I prevented her execution," Ocalan has said. After the 1991 Gulf War, the PKK gained new bases and arms supplies in Kurdish-held northern Iraq.
Fanatically loyal, his rebels died fighting in snow-covered mountains while he spent his time at a villa in Damascus or in the plains of the Syrian-controlled Bekaa Valley in Lebanon, where he had a training camp.
Ocalan declared a unilateral ceasefire in March 1993 in exchange for the start of political talks with Ankara, but the ceasefire ended just two months later.
In December 1995, he declared another ceasefire, and again on September 1st, 1998, but the Turkish government rejected them all.
Last October, Ocalan fled from Syria to Moscow following negotiations between Ankara and Damascus that he feared would end in his extradition. His flight took him on to Rome a month later, where he was arrested, triggering heated demands by Turkey for his extradition and protests by Kurdish nationalists demanding his release.
Rome refused to hand Ocalan over. Instead, he was placed under house arrest and finally, in January, allowed to leave Italy.
After failed attempts to re-enter Russia and enter the Netherlands to plead his case before the International Court of Justice, Ocalan sought asylum in Athens.
On February 15th, he was captured by a Turkish commando unit in Kenya after he took refuge in the Greek ambassador's residence in Nairobi.
He has been on trial for treason at the prison island of Imrali since May 31st.