Yemen's President Ali Abdullah Saleh was the fourth Arab leader to be forced from power.
Demonstrations calling for the end of his 33-year rule began in January 2011. Mr Saleh promised not to seek re-election, but the protests spread. Security forces and Saleh supporters launched a crackdown that eventually left between 200 and 2,000 people dead.
In April 2011, Mr Saleh's General People's Congress (GPC) agreed to a Gulf Co-operation Council-brokered deal to hand over power, but the president refused to sign. This prompted the Hashid tribal federation and several army commanders to back the opposition, after which clashes erupted in Sanaa. In June 2011, Mr Saleh was seriously injured in a bombing and travelled abroad for medical treatment.
He returned to the presidential palace in September 2011 amid renewed clashes. It was not until November 2011 that he signed the deal that saw his deputy, Abdrabbuh Mansour Hadi, assume power and form a unity government. Mr Hadi was sworn in for a two-year term as president in February 2012 after an election in which he stood unopposed.
Where are we now?
Since taking power, President Hadi has struggled to tackle widespread poverty and malnutrition, an Islamist insurgency led by al-Qaeda, a secessionist movement in the south, and Zaidi Shia rebels in the north. A National Dialogue Conference involving rival political, tribal, religious and social groups, is being held as part of the process to draft a new constitution and hold democratic elections in February 2014.