"Unity in diversity" was adopted as the official motto of the European Union in 2000, referring to the uniqueness of each of the nations belonging to the EU as well as to the intention of all the nations belonging to the organization to forge a common identity. Very soon after its adoption, the motto was changed to "United in diversity." Each member of the EU expresses the motto in its own language.
In choosing the motto "Unity in diversity" or "United in diversity," the EU wanted to express the intention of the organization to work jointly for prosperity and peace throughout Europe while at the same time acknowledging that each member nation brings to the table its own unique traditions and language that help to form its individual identity as a country.
The Preamble to the EU's Constitutional Treaty sets out the meaning of the phrase by pointing out that while the citizens of each European nation are proud of their own nation's heritage, history and national identity, collectively they have decided to transcend the differences and divisions that have been at the heart of European conflicts through history to seek out a common destiny. While that common destiny is a goal of the EU, however, the call for "diversity" acknowledges a respect for the rights of each nation's citizens.