Philippe SIUBERSKI - European royals and diplomats gathered in Belgium on Thursday to mark the 200th anniversary of the Battle of Waterloo, a turning point for the continent which still touches a nerve and stirs national passions.

"Waterloo, the folly and the grandeur. The horror and the genius. The tragedy and then the hope," Belgian Prime Minister Charles Michel said in an opening address under leaden skies.

The stress was on modern-day reconciliation and the sacrifice of some 47,000 dead or wounded soldiers on the fields around the small drab town just south of Brussels, the target of Napoleon's ill-fated drive north in June 1815.

France and Germany however only sent their ambassadors to a ceremony that attracted kings and dukes, reflecting the fact that history still runs deep in a corner of the continent scarred by centuries of war.

Just as two centuries ago when the French emperor faced off against allied forces, it rained overnight and the skies were overcast again for the ceremonies, carried live on Belgian television.

Michel called for reconciliation through the "European project" and its promise of peace despite modern-day challenges of conflict on its borders in Ukraine and economic worries. "The enemies of yesterday are the allies of today," said Michel. "This reality, it is the European project."

France ambivalent

The battle was a pivotal moment in European history, when around 93,000 French troops led by Napoleon faced off against 125,000 British, German and Belgian-Dutch forces commanded by the Duke of Wellington and Field Marshal Bluecher.

Napoleon was exiled to the island of Saint Helena in the south Atlantic Ocean, where he died in 1821. The victors redrew the map of Europe and the continent enjoyed almost a century of relative peace until the carnage of World War I tore it apart again.

Thursday's solemn ceremonies in Belgium began at 11:00 am (0900 GMT), the moment the first musket balls flew.

In Britain, the focus was on a service at St Paul's Cathedral attended by the heir to the throne Prince Charles and his wife Camilla.

On Wednesday, Charles had unveiled a memorial at the Hougoumont Farmhouse, where allied forces fought off repeated French attacks as Napoleon desperately sought to break their lines.

Just nearby stands the Waterloo monument, a massive mound topped by a defiant lion looking south which was completed in 1826 when Belgium was part of Holland and is said to be a warning to France never to come this way again. Such sensitivities linger, especially for France which now sees itself as a pillar of the European Union alongside Germany.

French Prime Minister Manuel Valls was ambiguous at best about the ceremonies. "I heard it said this morning that President (Francois Hollande) and myself should have been there so that we could shed our tears over this fearsome moment for our country," Valls said.

Hollande was meanwhile due to attend ceremonies marking the June 18, 1940 rallying call issued by General de Gaulle over the BBC for resistance against German forces in France.

For France, that June 18 date is a badge of honour when the country found its nerve again after a crushing defeat and dared to challenge the Nazi invader.

As for Napoleon, French Defence Minister Jean-Yves Le Drian appeared to sum up the dilemma - he had many great achievements but also "certain failures, this drive for power and extending borders which was not right."

Belgium angered France this month by minting a special 2.5-euro Waterloo commemoration coin after France forced it to scrap a two-euro coin saying it would cause an "unfavourable reaction in France."

Thousands of spectators

A total of 200,000 spectators are expected to make their way to Waterloo, starting with Thursday's commemorative service and ending with two days of battle re-enactments on Friday and Saturday.

Belgium's King Philippe led the attendance, which included the Grand-Duke of Luxembourg and the Duke of Kent, the cousin of Britain's Queen Elizabeth II, along with Frans Timmermans, the first vice-president of the European Commission.

The absence of Hollande and German Chancellor Angela Merkel was cause for regret.

"It's a shame," Charles Bonaparte, a descendant of Napoleon's brother Jerome, said Wednesday.

Among those proudly present were descendants of the top commanders on the day - Dutch King Willem-Alexander, whose ancestor the Prince of Orange was wounded at Waterloo; Prince Jean-Christophe Napoleon Bonaparte; the current Duke of Wellington and Prince Nikolaus Bluecher von Wahlstatt, whose illustrous forerunner led the Prussians who arrived just in time to save the day for the allied forces.

The four men laid ribbons of orange, red, black and blue to recall the army standards flown, under a cannon ball and then joined hands in a gesture of reconciliation.