European leaders arrived for a state dinner at Bellevue castle in Berlin on Saturday, as the European Union prepares to celebrate its 50th anniversary.
The dinner followed a concert at the Berlin Philharmonic Concert Hall where European leaders watched one of the world's leading orchestras.
German Chancellor Angela Merkel has challenged her fellow European Union (EU) leaders to back a fundamental renewal of the EU over the next two years, hoping the summit to celebrate the achievements of the bloc's first 50 years will point the way out of deadlock over the stalled constitution.
She said they had to send a clear message to the EU's 490 (m) million citizens on where the union was going, highlighting Germany's drive to overhaul the treaty that underpins the way the EU does business by 2009.
Germany holds the EU's rotating presidency and is leading efforts to end a two-year hiatus in Europe's drive for closer unity following the rejection of the bloc's draft constitution by French and Dutch voters in 2005.
Merkel hopes to rekindle popular support with a clear statement of the EU's achievements, from tearing down trade barriers to bolstering once-fragile democracies in Spain, Portugal, Greece and Eastern Europe and taking a world lead in development aid and fighting global warming.
The summit marks the 50th anniversary of the signing of the Treaty of Rome by six core countries of what was called the European Economic Community.
Merkel told reporters on Saturday that she was confident the 27 EU governments could overcome their deep differences over the EU's future by the 2009 deadline.
Anxious to ensure those differences do not overshadow the EU's anniversary party, leaders will leave out any direct reference to the constitution in their "Berlin Declaration" which will instead highlight the EU's achievements.
After a spate of last-minute diplomacy, Merkel did manage to secure agreement on the wording of the declaration, which the Germans, at least, see as pointing the way out of the constitutional deadlock over the next two years.
Merkel is pushing a timetable that includes a summit in June to launch six months of negotiations to draw up a revised EU treaty that could be ratified by all EU nations by 2009.
However, many see the schedule as over-ambitious given the level of division over how much of the deadlocked constitutional treaty should be saved.
Germany and Italy want to preserve much of the substance of the original text, while the Dutch insist that a new treaty must, in content, scope and name, differ from the constitution.
The Poles and British are wary about any changes that shifts power from national capitals to EU headquarters, and the Czechs are opposed to setting a date for concluding the new treaty.
Substantive talks on the constitution are unlikely to get under way until after the French presidential election in April, which will see the departure of Jacques Chirac, who is attending his last EU summit in Berlin after 12 years in power.