[1] It was not until the Easter Rising of 1916, when it was raised above Dublin's General Post Office by Gearóid O'Sullivan,[4] that the tricolour came to be regarded as the national flag.

In its advisory role, the department has issued guidelines to assist the use of the flag; these state that it should be rectangular in shape, its length should be double its width, and the three coloured pales – green, white and orange – should be of equal size and vertically disposed.

His title came from the Principality of Orange but his power from his leadership as Stadtholder of the Netherlands, a Protestant bastion from the 16th century.

The white in the centre signifies a lasting peace and hope for union between Protestants and Catholics in Ireland.

[8] The flag, as a whole, is intended to symbolise the inclusion and hoped-for union of the people of different traditions on the island of Ireland, which is expressed in the Constitution as the entitlement of every person born in Ireland to be part of the independent Irish nation, regardless of ethnic origin, religion or political conviction.

[8][13] (Green was also used as the colour of such Irish bodies as the mainly-Protestant and nonsectarian Friendly Brothers of St. Patrick, established in 1751.)

[15][16] Variants of different guises are utilised to include, for example, various emblems of Ireland, such as the presidential harp, the four provinces or county arms.

[citation needed] A green flag featuring a harp is described as being used by Eoghan Ruadh Ó Néill in 1642.

[citation needed] 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.

At a meeting in his native city of Waterford on 7 March 1848, Thomas Francis Meagher, the Young Ireland leader, first publicly unveiled the flag from a second-floor window of the Wolfe Tone Club as he addressed a gathered crowd on the street below who were present to celebrate another revolution that had just taken place in France.

[8] John Mitchel, referring to the tricolour of green, white and orange that Meagher had presented from Paris at a later meeting in Dublin on 15 April 1848, said: "I hope to see that flag one day waving, as our national banner".

[8] Although the tricolour was not forgotten as a symbol of the ideal of union and a banner associated with the Young Irelanders and revolution, it was rarely used between 1848 and 1916.

[8] In 1850 a flag of green for the Roman Catholics, orange for the Protestants of the Established Church and blue for the Presbyterians was proposed.

When the Free State joined the League of Nations in September 1923, the new flag "created a good deal of interest amongst the general public" in Geneva.

[33] The collier Glenageary may have been the first ship to arrive in a British port flying the tricolour on 8 December 1921, two days after the Anglo-Irish Treaty was signed.

[34][35][36] Some masters of Irish ships were charged by HM Customs and Excise and fined by Admiralty courts for flying an "improper ensign".

[45] In 1964, the enforcement of this law by the Royal Ulster Constabulary at the behest of Ian Paisley, involving the removal of a single tricolour from the offices of Sinn Féin in Belfast, led to two days of rioting.

[44] In Northern Ireland, each community uses its own flags, murals and other symbols to declare its allegiance and mark its territory, often in a manner that is deliberately provocative.

[52] Under the 1998 Good Friday or Belfast Agreement, it was recognised that flags continue to be a source of disagreement in Northern Ireland.

A Sinn Féin Lord Mayor of Belfast, Alex Maskey, displayed both flags in his own offices causing some controversy.

[58][59] Some institutions in Great Britain, such as the BBC, have previously and mistakenly used the tricolour to represent Northern Ireland.

[60][61] The Department of the Taoiseach has issued guidelines to assist persons in giving due respect to the national flag.

[65] On ceremonial occasions when the national flag is being hoisted or lowered, or when it is passing by in a parade, all present should face it, stand to attention and salute.

The national flag should never be defaced by placing slogans, logos, lettering or pictures of any kind on it, for example at sporting events.

Care should be taken at all times to ensure that the national flag does not touch the ground, trail in water or become entangled in trees or other obstacles.

[70] It is the normal practice to fly the national flag daily at all military posts and from a limited number of important State buildings.

On these occasions the national flag is flown from all State buildings throughout the country which are equipped with flagpoles, and many private individuals and concerns also fly it.

[71] The flag of the Ivory Coast has a similar colour layout to the Irish one, but with the orange on the hoist side and a shorter proportion (2:3 instead of 1:2).

When the Ivory Coast athlete, Murielle Ahouré, celebrated winning the 2018 world indoor 60-metre dash in Birmingham, she borrowed an Irish flag from a spectator and reversed it.

[72] Due to this similarity, in Northern Ireland, Ulster loyalists have sometimes desecrated the Ivorian flag, mistaking it for the Irish one.