Enlargement of the European Union and "morally imperative", which reflected the desire of the EU to admit these countries as members, even though they were less developed than the Western European countries. Following this Romania and Bulgaria, though were deemed initially as not fully ready by the Commission to join in 2004, acceded nevertheless on 1 January 2007. These, like the countries joining in 2004, faced a series of restrictions as to their citizens not fully enjoying working rights on the territory of some of the older EU members. Bulgaria and Romania are not yet members of the Schengen area; however, their citizens can travel
European Union Slovenia joined the Union. In 2007, Bulgaria and Romania became EU members. The same year, Slovenia adopted the euro, followed in 2008 by Cyprus and Malta, by Slovakia in 2009, by Estonia in 2011, by Latvia in 2014, and by Lithuania in 2015. On 1 December 2009, the Lisbon Treaty entered into force and reformed many aspects of the EU. In particular, it changed the legal structure of the European Union, merging the EU three pillars system into a single legal entity provisioned with a legal personality, created a permanent President of the European Council, the first of which was