With Irish immigration to the United States of America in the 18th-century there arose Irish ethnic organizations. One of the earliest was formed under the name of Irish Charitable Society and was founded in Boston in 1737. In the late 18th-century other organisation were formed from a higher level of awareness of what it meant to be Irish; this new awareness would be found in the sensibilities of new Irish immigration.These new organisations weant by varying names, most notably the Ancient and Most Benevolent Order of the Friendly Brothers of Saint Patrick, founded in New York in 1767, Society of the Friendly Sons of Saint Patrick for the Relief of Emigrants in Philadelphia in 1771, and the Friendly Sons of Saint Patrick also formed in New York in 1784.
In the later part of the 1780s, a strong nationalist character began to grow in these organisations and amongst recently arrived Irish immigrants. The usage of Celtic traditions helped solidify this sense of nationalism and was most noticeably found in the use of the name "Hibernian."
In 1858, The Irish Republican Brotherhood, was founded in Dublin by James Stephens. This organisation grew out of the initiative of Irish immigrants travelling to the United States of America. The initial decision to create this organisation came about after the James Stephens consulted, through a special emissary Joseph Denieffe with John O'Mahony and Michael Doheny who were members of a group called the Emmet Monument Association which later evolved into Clan na Gael.
In response to the Irish Republican Brotherhood (IRB)in Dublin, its sister organization was founded in New York as Clan na Gael. The head of the organization was John O'Mahony and this arm of Fenian activity in America caused a surge in radicalism among groups of Irish immigrants. In October, 1865, the Fenian Philadelphia Congress met and appointed the Irish Republican Government in the U.S.A. In 1865 in Ireland the newspaper The Irish People owned by the IRB was raided by the British and the IRB leaders were locked up. Abortive uprisings occurred in 1865 and 1867 but the British remained in control of Ireland.
Derived from veterns of the American Civil War, a Fenian army was also formed. In March of 1868, 100,000 Fenian members held an anti-English demonstration in New York. Within the Fenian organization, two military outlooks grew in friction with each other. One, called the O'Mahony Wing, which wanted to invade Ireland, the other,called the Senate Wing, wanted the Fenian Army to attack British soldiers in Canada.
The less radical and utopian plan won out and on the night of May 31, 1866, a Fenian Army division crossed the border into Canada. 800 Fenians attacked Fort Erie and after defeating Canadian militia at Ridgeway were forced to withdraw when the US Army cut off reennforcements and arrested Fenians crossing into Canada. The Fenians at Erie retreated back to the U.S., but on June 7th, new divisions of Fenian groups crossed the border into Canada from Vermont. After this event, the level of American support for the Fenian cause diminshed quickly as the Irish were seen as a threat to stability in the region.
The Irish were still seen as a foreign people within the borders of the American state; their existence within America was seen primarily as temporary camps of immigrants who planned to stay in America only as long as the British stayed in Ireland. Upon their removal from Irish soil, it was believed, the Irish immigrants would return to their native land. The Fenian invasion of Canada is seen as an astonishing example of immigrant group activity in U.S. history and Irish nationalism has itself become something of an exception among the American melting pot. Very few U.S. immigrants concerned themselves with their mother country as did the Irish.
After the Fenian military failure, the Irish Republican Brotherhood became an illegal entity under American law. The organization's deeds were centered on national freedom-fighting including acts of terrorism. Leaders of the Clan carried out their own foreign policy, and courted support from ambassadors of nations they perceived as enemies of England. When the chances of war with England were fading, Clan na Gael looked for allies among other Irish national groups, and on the cusp of the 1870 - 1880s, their attempts at coalition building were successful. From amongst the many Irish nationalist organisations, a coalition was formed among Clan na Gael, parts of the clergy and sections of the Irish Land League.
Clan na Gael was known for rescuing convicted Fenians from a remote Australian prison and, under the leadership of John Devoy, would eventually be successful educating Americans about the movement. Devoy, along with Roger Casement, were able to bring together both the American and German support in the years prior to the Easter Rising. Clan na Gael became the largest single financier of both the Easter Rising and the Irish War of Independence.
The 1880s saw the solidification, at least within America, of Irish ideological orientations with Nationalist sentiment finding its home within Clan na Gael. The more people-agrarian moderate ideology found its ideological bretheren within the Irish Federation of America. The third ideological strand was party connected to the union and socialist movement and found support with the Knights of Labor.
In 1891, a moderate offshoot of the Clan na Gael broke away and formed an organization under the name of Irish National Federation of America with T. Emmet as president. The federation supported the National Party in Ireland, a shoot-off of Charles Stewart Parnell's Home Rule Party and the Irish National Land League.
The objective of Clan na Gael was to secure an independent Ireland and to assist the Irish Republican Brotherhood in achieving this aim. Too this end, Clan entered into alliances with any nation allied against the British; with the outbreak of the First World War in 1914, Clan found its greatest ally in Imperial Germany and it was with their help the Easter Uprising would come about. Imperial Germany aided Clan na Gael by selling those guns and munitions to be used in the uprising of 1916, Germany had hoped that by distracting Britain with an Irish uprising they would be able to garner the upper-hand in the war and affect a German victory on the Western Front.