The flag was adopted by the Irish Republic during the Irish War of Independence (1919–1921).The flag's use was continued by the Irish Free State (1922–1937) and it was later given constitutional status under the 1937 Constitution of Ireland.In its advisory role, the Department has issued guidelines to assist persons in their use of the national flag.
In 1883, a Parnellite tricolour of yellow, white and green, arranged horizontally, was recorded.
Down to modern times, yellow has occasionally been used instead of orange, but by this substitution the fundamental symbolism is destroyed.
There are exceptions to the general beneficent theory.
Green was also used as the colour of such Irish bodies as the mainly-Protestant and non-sectarian Friendly Brothers of St. Occasionally, differing shades of yellow, instead of orange, are seen at civilian functions.
The oldest known reference to the use of the three colours of green, white and orange as a nationalist emblem dates from September 1830 when tricolour cockades were worn at a meeting held to celebrate the French Revolution of that year — a revolution which restored the use of the French tricolour.