The Flight of the Earls

September 14, 1607:

The Flight of the Earls (Irish: Imeacht na nIarlaí / Teitheadh na nIarlaí) took place on 14 September 1607, when Hugh Ó Neill of Tír Eóghain, Rory Ó Donnell of Tír Chonaill and about ninety followers left Ireland for mainland Europe.
The earls left from the town of Rathmullan on Lough Swilly on a French ship with some of the leading Gaelic families in Ulster. This town was said to have witnessed the end of the old Gaelic order, in the sense that the earls were descended from Gaelic clan dynasties that had ruled their parts of Ulster for centuries. The Flight of the Earls was a watershed in Irish history, as the ancient Gaelic aristocracy of Ulster went into permanent exile. Despite their attachment to and importance in the Gaelic system, the Earls' ancestors had also accepted their Earldoms from the English-run Kingdom of Ireland in the 1540s, under the policy of surrender and regrant. Some historians argue that their flight was forced upon them by the fallout from the Tudor conquest of Ireland, others that it was a strategic mistake that cleared the way for the Plantation of Ulster.

The late Tomas Cardinal O’Fiaich, Archbishop of Armagh, gave a lecture at Rathmullan in September 1988 and recounted that the Earl of Tyrone allegedly “had a gold cross which contained a relic of the True Cross, and this he trailed in the water behind the ship, and according to O’Ciainain, it gave some relief from the storm” during the crossing to Quillebeuf-sur-Seine in Normandy, France; they finally reached the Continent on 4 October 1607. The significance of this act is also underlined by the fact that the date of the exile from Rathmullan was the Feast of the Exaltation of the Holy Cross. This supposed relic of the True Cross was probably a minor relic taken from that kept at Holy Cross Abbey which they had previously visited en route to Kinsale in 1601.

The Red Hand of Ulster, also
known as the Red Hand of O'Neill

From Wikipedia:

The Red Hand was later included in the Northern Ireland flag and on the shields of counties Cavan, Tyrone, Londonderry Derry, Antrim and Monaghan. It is also used by many other official and non-official organisations throughout the province of Ulster.
The Red Hand can be regarded as one of the very few cross-community symbols used in Northern Ireland. Due to its roots as a Gaelic Irish symbol, nationalist/republican groups have used (and continue to use) it often – for example the republican Irish Citizen Army, the republican National Graves Association, Belfast, the Irish Transport and General Workers Union and numerous GAA clubs in Ulster. However, after the creation of Northern Ireland, loyalist groups began to use it widely – for example the Red Hand Commandos, Red Hand Defenders and Ulster Defence Association, among others.
Due to its usage by loyalist paramilitaries, those unfamiliar with Irish history have believed it to be a solely loyalist symbol. In 2005 former Miss Northern Ireland, Zöe Salmon, caused controversy when she selected the Red Hand as a symbol to represent Northern Ireland in a competition for Blue Peter. David Miller, a sociology professor from Strathclyde University in Scotland, complained to the BBC, saying that "like the swastika the Red Hand has been misappropriated ... it is the symbol of the unionists."^] Michael Copeland, an Ulster Unionist party assembly member, described the row as “political correctness gone mad”.