Paris - Since its birth in 1957, the European Union has weathered many crises and Britain's decision to leave is among the most severe.
With a draft Brexit deal reached Thursday, but still requiring British parliamentary and full EU approval, here is a recap of other testing times in the history of the union.
- De Gaulle vetoes Britain -
In 1963 French President Charles de Gaulle vetoes Britain's entry into the European Economic Community, the precursor to the European Union that was set up in 1957 by six countries -- Belgium, France, Germany, Italy, Luxembourg and the Netherlands.
He does so again in 1967 but Britain finally joins in 1973.
- 'Empty Chair' -
In 1965, in what is known as the "Empty Chair" crisis, a stalemate that arises from a dispute over budget funding sees de Gaulle withdraw French representatives from community activities for seven months.
What is the European Union and how does it function?
- Thatcher fights for rebate -
In 1979 British Prime Minister Margaret Thatcher demands a rebate for her country's contribution to the European budget, reportedly declaring: "I want my money back."
After five years of fierce negotiations, London secures its annual rebate at a 1984 summit.
- Danes reject treaty -
In 1992 Danes shock Europe when they turn down the Maastricht Treaty that established the EU and laid the groundwork for European monetary union.
They barely approve an amended version in 1993 after Denmark is granted greater autonomy in defence, currency, citizenship matters and judicial cooperation.
- European Commission resigns -
In 1999 the European Commission led by Luxembourg's Jacques Santer resigns en masse following a report denouncing its responsibility for fraud.
- Austria sanctioned -
In 2000 Austria's conservative People's Party (OeVP) picks the far-right Freedom Party (FPOe) as its junior coalition partner, shocking Europe and leading to EU sanctions on the country for several months.
The FPOe again enters government in 2017, this time without angering Brussels.
- Constitution shot down -
In 2005 French voters reject a draft European constitution proposed by the Treaty of Lisbon, followed three days later by Dutch voters.
Shocked European leaders manage to get a treaty ratified late 2009, with provisions designed to improve the functioning of the enlarged EU institutions.
- Greek debt -
In 2009 Athens reveals a sharp rise in its public deficit, unleashing a financial crisis across the eurozone.
First Greece, then Ireland, Portugal, Spain and Cyprus seek aid from the EU and the International Monetary Fund, which demand strict fiscal discipline in return. Several heads of government fall as austerity measures provoke a popular backlash.
Chronology of the Greek financial crisis
- Migration crisis -
In 2015 Europe is hit by its most serious migration crisis since the end of World War II.
EU leaders struggle to work out a joint action plan, with several EU members refusing to take a share of refugees.
In September 2015 Germany, which had until then had been welcoming refugees, restores border controls, a move quickly followed by other countries.
- Brexit -
In June 2016 Britons vote 52 percent to 48 percent in favour of quitting the EU, putting Britain on course to become the first country to quit the bloc.
London and Brussels engage in tough divorce negotiations -- Britain's Prime Minister Theresa May resigning along the way -- and the deadline is pushed back twice to October 31, 2019.
On October 17 London and Brussels announce a draft Brexit deal, which will need to be approved by the British parliament and EU leaders.
How did Britain vote in the 2016 referendum?