1. Ireland's EU membership was kiboshed in 1963 by France's President de Gaulle. He said 'Non' to Britain putting Ireland's hopes beyond reach.
2. Eamon de Valera had been saying 'Nil' to Europe before de Gaulle's rebuff.
3. It was only when Sean Lemass became Taoiseach in 1959 that Irish membership efforts really got under way.
6. Irish fishing and coastal communities were the big EU losers. Access to fish-rich Irish waters cost billions of euro.
7. Two Irish EU fishery claw-back efforts in 1975 and 1985 gave only temporary and limited remedies.
8. Voters in Norway twice rejected EU membership. Fishery issues loomed large in their decision but they also have the cushion of coastal oilfields.
10. Senator Jim Dooge headed an EU expert committee in 1985 which planned the border-free 1992 Single Market for people, goods and services.
11. The EU Court of Justice in 1990 outlawed an Irish rule that shoppers had to be 48 hours outside the jurisdiction to qualify for duty-free or duty-paid drink and tobacco.
12. Ray MacSharry as Finance Minister made the '48-hour rule' in 1987 but he was Ireland's EU Commissioner by the time of the case.
15. Ireland has had nine EU Commissioners over the 40 years to date. There has been just one woman, the current incumbent, Maire Geoghegan-Quinn whose term ends in December 2014.
16. Ireland's second EU Presidency was July – December 1979 headed by Taoiseach Jack Lynch.
17. The main 1984 leaders' summit at Dublin Castle was dominated by British Prime Minister Margaret Thatcher's demands for a big cut in Britain's contribution.
18. The EU's flag since the 1950s is 12 gold stars, each with five points, on a blue background. Unlike the US, the EU does not add a star when a new member joins.
19. The European Parliament officially has two centres of operation in Brussels and Strasbourg.
20. The elected MEPs do most of their work in Brussels and meet for five days each month in the French city of Strasbourg.
21. Ireland's first judge in 1973 at the EU Court of Justice was Cearbhall O Dalaigh. He came back to Ireland in 1974 to be appointed President with all-party support but quit in 1976 after a huge row.
22. The Irish language had limited EU recognition from 1973. In January 2007 it became the 23rd official EU language.
23. Seven out of 10 Irish voters voted in the first EU referendum in 1972. Turnout has been falling in various EU referendums since then.
24. Lowest voter turnout was in 2001 when only 35pc voted on the EU Nice Treaty.
25. Ireland's third EU presidency was July-December 1984 headed by Taoiseach Garret FitzGerald.
26. The Dublin Castle leaders' summit in December 1984 saw a huge security operation for Prime Minister Margaret Thatcher six weeks after the IRA bomb at her Brighton Hotel killed five people and injured 31.
27. The Irish Farmers' Association has had an office in Brussels since 1973. It was first headed by a future Fine Gael leader and government minister, Alan Dukes.
28. Three former IFA presidents – TJ Maher, Paddy Lane and Alan Gillis – were later elected MEPs.
29. IBEC's, the business and employers' group, best-known Brussels representative was Peter Brennan who ran the operation for 15 years from 1986 to 2001.
30. The Irish Supreme Court has been called upon to adjudicate on how the EU affects the Irish Constitution on several occasions. In the 1987 Crotty Case it ruled that major EU treaties require a referendum.
31. Taoiseach Charlie Haughey headed Ireland's fourth EU presidency in 1990. His term saw the end of partition ... in Germany – not Ireland.
32. Ireland's fifth EU presidency in 1996 was headed by Taoiseach John Bruton. Its main focus was preparation for the euro.
33. Irish voters' rejection of the Lisbon Treaty delayed the installation of a new EU Commission in late 2003.
34. The EU Commissioner's job has always been seen as the biggest political plum in the Taoiseach's gift.
36. Of the nine Commissioners to date seven are former cabinet ministers and two served as Attorney General.
37. Taoiseach Albert Reynolds' short term in office, 1992-94, coincided with setting ground rules for the biggest ever overseas cash infusion totalling €18bn between 1988-2008 in regional and social fund grants.
38. Irish agriculture has been the big EU beneficiary netting over €2bn per year at its height in the 1990s. But it has largely been about managing dramatic change with farm numbers falling by 20 per cent between 1991 and 2011.
39. There were nine EU member states when Ireland joined in 1973. This grew by five different bouts of new state recruitment to the current 27 member states.
40. Taoiseach Bertie Ahern headed Ireland's sixth EU presidency. The high point was EU membership for eight new former East Bloc states.