On Saturday, leaders from across the continent will come together to mark the 60th anniversary of the Treaty of Rome.
Seen by many as the founding document of European political and economic cooperation, the anniversary will be celebrated with drinks receptions and panel events hosted by Brussels diplomats.
Leaders of the member states will also use the day to pledge that the door remains open for the future enlargement of the bloc.
In the UK, the anniversary will be more poignant due to the imminent triggering of Article 50. Protesters will use the day to demonstrate the depth of their anti-Brexit sentiment outside Parliament.
Signed on the 25th March 1957, the Treaty of Rome brought the existing post-war European organisations together into a single structure: the European Economic Community.
The Community as it was known, was to become the modern Union, and would eventually be credited with ensuring peace on the continent.
The original six member states – West Germany, France, Italy, Luxembourg, Belgium and the Netherlands – came together and introduced policies which would form the EU that we recognise today.
The free movement of labour, the customs union, the European Commission and the European Investment Bank all stem from the Treaty. For the most ardent Europhile, the treaty represents the very best of the European project.
Usually in the UK, the Treaty’s anniversary passes unnoticed by the public and is largely ignored by the press. The UK never signed the original Treaty and didn’t join the Community until 1973 after the enactment of the European Communities Act.
But this year the annual celebrations have garnered significantly higher levels of attention.
Brexit and the complications that the anniversary have inflicted upon the Prime Minister’s self-imposed trigger deadline have brought the Treaty to the fore.
Just like dumping a partner on their birthday, the Prime Minister has had to be careful about when to officially begin proceedings.
In order not to complicate the negotiations further, she’s opted not to spoil the party and will wait until next week.
But it remains the case that Brexit will cast a shadow over the celebrations.
Just as the protesters outside Parliament on Saturday will be thinking about their place on the continent, EU officials will no doubt also use the occasion to reflect on the future of the European project.
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