The term Fenian, as I originally understood it, described anyone who opposed a British presence in Ireland. Of course there's more to it than that. It is a term that originated in the legendary tales of Celtic warriors and was adopted by early Irish-American visionaries. It has evolved into a term that is an easy insult for some, and worn as a badge of honor by others. Fenians have been around since the third century A.D.
Originally a group of knights, the Fianna were similar to King Arthur and the Kights of Camelot. They held high ideals of chivalry and national unity. One early story described a temptation to give up Ireland. In return they would gain the world and the country of everlasting youth. The Fenians did not do so, and ended up defeating the temptor.
The Fenian Brotherhood was an organization started in the United States by John O?Mahony in 1858. O?Mahony and James Stephens, both members of the Young Ireland Rising of 1848, worked together to gain support for an uprising in both Ireland and the US. Stephens was instrumental in establishing the Irish Revolutionary Brotherhood (later known as the Irish Republican Brotherhood) in Ireland. The object of Stephens, O'Mahony, and other leaders of the movement was to form a league of Irishmen in all parts of the world against British rule in Ireland. The organization was modelled on that of the Jacobins of the French Revolution; they even formed a "Committee of Public Safety" in Paris, with a number of subsidiary committees and affiliated clubs. The Fenians were soon found in Australia, South America, Canada, and above all in the United States, as well as in the large cities of Great Britain such as London, Manchester, and Glasgow.
One of the main goals of the Fenian Brotherhood was to invade Canada in order to ransom it back to Britain in return for Irish freedom. Despite several raids conducted between 1866 and 1871, the Fenians were never successful. There was also a Fenian rising in Ireland in 1867 that was unsuccessful. Despite their lack of success on the battlefield, the Fenians true achievement was to pass on the ideal of Irish independence to the next generation.