A black and white photograph on Rached Ghannouchi's desk shows him as a young activist proclaiming the birth of a Tunisian Islamist movement that three decades later would win the first elections after the Arab uprisings.
But having inspired Islamists across the Middle East by rising to power following Tunisia's 2011 popular revolution, Ghannouchi's moderate Islamist Ennahda party now finds itself within weeks of voluntarily stepping down.
Ennahda last week agreed its coalition government would resign, but only after negotiations with secular opposition parties to establish a temporary, non-party government to run the country until new elections.
Ghannouchi, the party's chairman, said in an interview that the ballot could be held early next year, and that Ennahda had not necessarily lost the chance to lead one of the Muslim world's most secular countries with strong ties to Europe.
"With regard to the election, we want it as quickly as possible. But realistically we are talking about spring next year," the soft-spoken 72-year-old said.
"The Tunisian people will decide at the elections whether this government has failed or not."
The deal to step down came after the murder of an opposition leader by suspected Islamist militants in July, which ignited months of protests, shut an assembly drafting a new constitution and threatened a transition seen as the region's most promising.
So Ennahda wants its political opponents to get back to work to draft the constitution, appoint an electoral body and set a date for elections as part of its resignation package.
"What we said to the opposition is very simple: Return to the assembly so you finish your work in finalizing the constitution and the election commission and we will give up government in return," he told Reuters.
"Give the Tunisian people who elected you the constitution they elected you to produce, and we will give up the government."
Since the 2011 revolt that toppled autocrat Zine El Abidine Ben Ali, Tunisia has struggled to reach consensus over what role political Islam should play in society.
Ghannouchi's Ennahda was one of the Islamist parties that rose to the fore after the "Arab Spring" revolts that toppled autocratic leaders in Libya, Egypt and Yemen.
Since then, though, Ennahda's support has slipped, Egypt's Islamist president has been ousted by the military and his Muslim Brotherhood violently suppressed, and many parts of Libya have fallen under the control of rival militias.
Even in Morocco, the Islamist party governing in a coalition has seen its political strength eroded.
But Ghannouchi, a scholar who sports a trim white beard and spectacles, rejected the idea that the setbacks suffered by Islamist movements in Egypt and other countries were a reversal of recent gains for political Islam.
"We may have a few dips on the way, but the trend is on the up," he said. "In the world of ideas, the only idea that is there in the Arab world is the Islamic idea, the idea that Islam and modernity go hand in hand, that Islam and democracy go hand in hand."
Tunisia's transition has been relatively peaceful compared with some of its North African neighbors, even with protests and attacks on secular Tunisians by conservative Islamists once suppressed under Ben Ali.
Ennahda initially won 40 percent of the seats in the assembly writing Tunisia's constitution, and it shared power in a coalition with two smaller secular parties as part of an initial transitional agreement.
The party's ascent opened fierce debate about the role of religion in politics in a country where many critics worried that rising Islamist influences might end up imposing Islam on liberal education and women's rights.
Ghannouchi, who fled into exile in London in 1989 as Ben Ali repressed Ennahda, has long promoted moderate Islamist policies.
But early on in the debate about the new constitution, religious conservatives demanded the inclusion of elements of Sharia, or strict Islamic law, adding to liberals' concerns.
Facing street protests, Ghannouchi's Ennahda resisted opposition attempts to pressure the government to resign, at one point calling the demonstrations a counter-revolution and bringing his supporters on to the streets.
But perhaps wary of the fate of Egypt's Brotherhood, Ennahda eventually accepted the idea of stepping aside for a caretaker cabinet.
Ennahda and its opponents have signed a formal agreement to sit down to talks, but negotiations now look unlikely to start until after the Eid Muslim holiday at the end of next week.
Although critics blame Ennahda for economic mismanagement, and for being soft on militants, Ghannouchi's party remains the most organized political organization in Tunisia, making it a force to be reckoned with going into any ballot.
The opposition, led by the Nida Tounes, which includes former members of Ben Ali's regime, and an alliance of smaller parties, is pushing for elections at a later date.
With Ennahda keen on a quick vote, the timetable for the ballot will likely be one of the sticking points in talks.
"We are ready ...to resign because we want the country to go to elections," Ghannouchi said. "This is the only justification for us to resign. It is nothing to do with failure."