English: A coat of arms of the European Union that is not officially adopted, composed of the 27 national coats of arms as quarterings on a single shield. This heraldic method, known as marshalling, is traditional across Europe for the representation of multi-national unions. Examples: the medieval union between Sweden, Norway and Denmark, the Union between Sweden and Norway (1814–1905), the United Kingdom of Great Britain and Northern Ireland (1707–present), the Holy Roman Empire (1765), the Kingdom of Spain etc.. Some arms, such as that of the Nugent-Brydges-Chandos-Grenville family, even contain houndreds of quarterings. The number of possible quarterings is unlimited.
Blazoning:
United Kingdom: Quarterly, first and fourth Gules three lions passant guardant in pale Or armed and langued Azure (for England), second quarter Or a lion rampant within a double tressure flory-counter-flory Gules (for Scotland), third quarter Azure a harp Or stringed Argent (for Ireland)
Ireland: Azure a harp Or stringed Argent (for Ireland)
etc.

The countries' coats of arms are placed in 5 rows of 5 columns, and in a lower 6th row with 2 equal-width quarters. The order of appearance of each country's coat of arms is defined by listing all countries names alphabetically in the language of the referred country. Looking at the picture above from left to right and from top to bottom, we can see the coats of arms of the following countries:

Austria	Belgium	Bulgaria			Cyprus	Czech Republic
Germany	Denmark	Estonia			Spain	Finland
France	United Kingdom	Greece			Hungary	Ireland
Italy	Lithuania	Luxembourg			Latvia	Malta
Netherlands	Poland	Portugal			Romania	Sweden
Slovenia			Slovakia