Ahmed Moaz al-Khatib, who resigned Sunday as Syria's opposition leader, is a former imam and moderate Islamist who rose from independent ranks as a respected figure of dissent against the Damascus regime.
His surprise resignation after just months in the post comes days after the election of a first rebel prime minister, Ghassan Hitto, and just over two years after the outbreak of a popular revolt against President Bashar al-Assad.
Khatib, who will be 53 this year, had reportedly wanted to quit for some time, objecting to an interim premiership.
He had been the lead cleric at the historic Umayyad Mosque in Damascus, and was arrested several times last year for publicly calling for the fall of Assad's regime.
Forbidden by the authorities from preaching, he fled Syria for Cairo and Qatar last year, and in November was elected to head the opposition Syrian National Coalition at a meeting in Doha.
Khatib, who is not allied to any political party, comes from a Sufi Muslim background and is unrelated to the Muslim Brotherhood or any other anti-regime Islamist party.
He studied international relations and diplomacy and has long advocated peaceful activism against the regime. Despite being a Muslim sheikh, he enjoyed the support of many secular regime critics.
Though Khatib's family comes from central Damascus, he played a key role in sparking the uprising in the Eastern Ghouta area, east of the capital, which is where some of the fiercest and best-organised rebel groups are based.
After his election in November, the Syrian National Coalition was recognised by dozens of states and organisations, including the United States, as the legitimate representative of the Syrian people.
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The choice of Khatib to head the reframed opposition surprised the international media, but nearer to home in Damascus activists who already knew him were overjoyed.
"We trust Sheikh Moaz al-Khatib as a person. He is Islamist and moderate at the same time. He has been respected for years," Abu Nadim, an activist in Douma east of Damascus, told AFP at the time.
Stylish and intellectual in appearance, Khatib with his salt-and-pepper beard and Western suits -- but never a tie -- has taken risks to impose his convictions, albeit with calm determination.
In February he surprised both his allies and the Assad regime by offering to open talks with the Damascus government, subject to conditions including the release of 160,000 detainees.
The Syrian regime rejected conditional talks as some of Khatib's detractors in the opposition labelled his offer traitorous and incoherent.
Khatib rejected such accusations. "I cannot accept that those who talk about negotiations are accused of treason," he said.
"Some have told me that men of politics do not talk this way... I say to them: I am just a revolutionary."
Born in 1960 to a family of prominent religious scholars, Khatib pursued a diverse range of academic disciplines, studying geophysics, political science, international relations and diplomacy, and Islamic studies.
From 1985 to 1991, he worked as a geophysics engineer at Al-Furat petrol company, a joint Syrian-international venture which has included Anglo-Dutch Shell.
In 1990, he succeeded his father, Sheikh Badr al-Din al-Khatib, as imam in the prestigious Umayyad mosque in central Damascus.
The father of four has lectured on Islam in Nigeria, Bosnia, Britain, the United States and The Netherlands.