Republic of Ireland (or Ireland) is a sovereign state in western Europe occupying about five-sixths of the island of Ireland. The capital and largest city is Dublin, located in the eastern part of the island, whose metropolitan area is home to around a third of the country's 4.6 million inhabitants.
The national flag of Ireland is also known as the Irish tricolour. It is a rectangular flag with an aspect ratio of 1:2 (width-to-length) and has equal areas of three colors - green, white and orange.
The colors symbolizes aspects of Irish traditions. The green represents the Gaelic tradition of Ireland (the Nationalists), the orange represents the followers of William of Orange in Ireland (the Unionist) and the white represents the aspiration for peace between them.
The flag was first used in 1916 during the Easter Rising when it was raised above the General Post Office building in Dublin. It was subsequently adopted by the Irish Republic during the Irish War of Independence from 1919-1921. It was later given constitutional status under the 1937 Constitution of Ireland.
Reference: all accessed 5 January 2015