FACTBOX: Who is Sudanese Islamist Hassan al-Turabi?

(Reuters) - Sudanese Islamist opposition leader Hassan al-Turabi was arrested on Monday after a weekend attack on the capital by rebels from Darfur's Justice and Equality Movement, who had been linked to Turabi in the past.

Here are some facts about Turabi.

* Turabi is an Islamist ideologue with respect in many parts of the Muslim world. He was born in 1932 in the Sudanese town of Kassala.

* He was the spiritual mentor behind the Islamist government of President Omar Hassan al-Bashir, who took power in a 1989 coup, but they later fell out.

* In the 1990s, when Sudan hosted al Qaeda leader Osama bin Laden, Turabi was seen as the driving force behind Khartoum's promotion of militant Islamist groups.

* Turabi supported former President Jaafar Nimeiri in his 1983 drive to Islamic Sudan. After they fell out in March 1985 Nimeiri's 16-year rule lasted only three weeks.

* Turabi has been locked up several times -- in 1985 by Nimeiri and in 2001 after a power struggle with Bashir. Released in October 2003, he was detained again in March 2004 when he was accused of plotting a coup against Bashir.

* Sudan released Turabi in June 2005, in a step towards reconciliation, but Bashir's government accused him of backing the Darfur rebels -- a charge both Turabi and the group deny.

* A lawyer, Turabi was educated at Edinburgh University and the Sorbonne in Paris. He is fluent in English and French.