Well, the Quadruple alliance was:
The United Kingdom
Austria
Prussia
Russia
It was an alliance made to combat France in case they decided to campaign again, like Napoleon did. Weirdly, France did join in 1818, however that was not your question.
The Quadruple alliance (at least this one) was originally started in 1813 with the same members, and renewed in 1815. So no country actually "joined" the alliance in 1815.
France
France
Italy dropped out of Triple Alliance to fight against the Austria-Hungary in May of 1915, and Germany in 1916.
The Grand Alliance was an alliance made during World War II, which joined together the United States, Great Britain, and the Soviet Union. The United States was led by Franklin Roosevelt, the Soviet Union by Joseph Stalin, and Great Britain by Winston Churchill.
In Europe the British had an alliance with Russia and France called the triple entente and a separate alliance with Belgium. Italy also joined GB later and Russia also pulled out.
Romania is a European country since it existed. What you are referring to is the organisation known as the European Union. It joined the European Union on the 1st of January 2007.Romania is a European country since it existed. What you are referring to is the organisation known as the European Union. It joined the European Union on the 1st of January 2007.Romania is a European country since it existed. What you are referring to is the organisation known as the European Union. It joined the European Union on the 1st of January 2007.Romania is a European country since it existed. What you are referring to is the organisation known as the European Union. It joined the European Union on the 1st of January 2007.Romania is a European country since it existed. What you are referring to is the organisation known as the European Union. It joined the European Union on the 1st of January 2007.Romania is a European country since it existed. What you are referring to is the organisation known as the European Union. It joined the European Union on the 1st of January 2007.Romania is a European country since it existed. What you are referring to is the organisation known as the European Union. It joined the European Union on the 1st of January 2007.Romania is a European country since it existed. What you are referring to is the organisation known as the European Union. It joined the European Union on the 1st of January 2007.Romania is a European country since it existed. What you are referring to is the organisation known as the European Union. It joined the European Union on the 1st of January 2007.Romania is a European country since it existed. What you are referring to is the organisation known as the European Union. It joined the European Union on the 1st of January 2007.Romania is a European country since it existed. What you are referring to is the organisation known as the European Union. It joined the European Union on the 1st of January 2007.
Bulgaria
No country joined the European Union in October 2007. Two countries did join in 2007, Bulgaria and Romania, but they both joined on the 1st of January 2007.
Greece joined what was then known as the European Economic Community in 1981. It is now called the European Union.
Yes. It joined in 2004.
Italy
No. althought the language has semitic roots, the country is in fact European. Malta joined the European union in 2004
The Netherlands.
Bulgaria.
The UK, Denmark, and Ireland join the European Union in 1973.
As of the 27th of June 2014, one country has joined the European Union since May 2007. That was Croatia, who joined on the 1st of July 2013.
Croatia joined the European Union in July 2013.