Moncef Marzouki and Beji Caid Essebsi face off on Sunday in Tunisia's second round of presidential voting to decide who leads the nation that sparked the Arab Spring.
Neither frontrunner was able to secure an absolute majority in the first round on November 23: Essebsi took 39.46 percent of votes cast and current president Marzouki 33.43 percent.
Sunday's presidential vote comes after Essebsi's secular Nidaa Tounes party won 86 seats in the October 26 legislative election, beating moderate Islamist movement Ennahda into second place with 69 seats.
Following are profiles of Essebsi and Marzouki:
Considered the favourite to become head of state despite being 88, Essebsi held key posts under Habib Bourguiba, the father of Tunisian independence, and under deposed dictator Zine El Abidine Ben Ali.
An anti-Islamist lawyer, Essebsi was prime minister after the 2011 revolt and organised parliamentary elections later that year.
His detractors accuse him of seeking to restore the regime of Ben Ali, who clung to power for 23 years before fleeing in January 2011, combining authoritarian rule with a degree of prosperity and stability for his people.
During campaigning before the first round, and in an interview with AFP, Essebsi defended the "right" of former Ben Ali regime figures to play a role in governing Tunisia alongside all political factions.
"We want a 21st century state, a progressive state," Essebsi said.
"What separates us from those people is 14 centuries," he said, in an allusion to the birth of Islam in the 7th century.
Essebsi is married and has two sons and two daughters.
Born in 1926, he denies that his age is a hurdle to the country's highest office.
"I have the age that I have," he told AFP, describing youth as "a state of mind".
The incumbent president was installed by parliament two months after December 2011 polls, the country's first election after the revolution.
Marzouki, a 69-year-old Strasbourg-trained neurologist born in 1945, was Ben Ali's bete noir throughout his political career and was forced to live in exile in France for a decade.
He is credited with having prevented Tunisia from being split into secular and Islamist camps, but critics accuse him of having forged a pact "with the devil" -- in reference to Ennahda which won the 2011 legislative polls -- to satisfy his political ambitions.
But Marzouki, named by Time magazine in 2013 as one of the world's 100 most influential people, has defended his coalition with the Islamists as the best way to protect democracy in Tunisia.
The father of two daughters has kept a low profile as president, showing up in public with his trademark collarless shirt and no tie, in stark contrast to the pomp of the Ben Ali years.
His thick glasses, receding hairline and craggy face have made him a favourite with political cartoonists.
Marzouki has warned that democracy in Tunisia is being threatened by "tyranny" and has urged voters to prevent a political comeback of the old guard.