Turkey and the European Union clinched a historic deal to launch membership talks on Monday despite deep public scepticism over whether the wealthy Western bloc will ever be able to absorb the teeming Muslim nation.
The opening ceremony was delayed until close to midnight by nearly two days of fierce wrangling over Austrian and Turkish objections to the EU's proposed negotiating mandate, reflecting profound distrust on both sides.
"We reached agreement, I am going to Luxembourg," Turkish Foreign Minister Abdullah Gul told reporters as he left the headquarters of his ruling Justice and Development Party (AKP) in Ankara to fly to meet the 25 EU foreign ministers.
Austria eventually accepted that the shared goal of the negotiations would be accession, not the lesser "privileged partnership" which many conservatives and Christian Democrats across Western Europe had sought.
In return, the EU made clear that its capacity to embrace the vast, poor Nato ally strategically located on the borders of Europe and the Middle East would be a key factor in the pace of Turkey's integration, as well as Ankara's progress in meeting strict criteria.
Negotiations are expected to last at least a decade and at least two EU members, France and Austria, have promised their voters a final say on Turkish accession in referendums.
"This historic European Union decision will have repercussions throughout the Islamic world," Portuguese Foreign Minister Diogo Freitas do Amaral told reporters.
"Probably it will displease Mr (Osama) Bin Laden, who has done everything to avoid this moment arriving," he said, referring to a struggle between pro-Western Turkish Muslims and Islamist militants who have declared war on the West.
Turkey, which made major progress on democracy and human rights just to qualify for starting talks, now faces a marathon effort to transform its political, economic and social system and implement 80,000 pages of EU law.