The IRA, and prior to that, the Fenians, were a problem for over a hundred years. They are also the best comparison to IS and islamic radicals of various stripes.
They were not geographically limited either, tell that to the people of the day. There were attacks of various kinds in Australia, Canada, USA, UK... all over. There were begrudging migrants/economic refugees who fleed famine, and amongst them, were some violent terrorists.
There was also an assassination attempt on Prince Alfred in 1868 by James O'Farrell. There were huge upsurges in Anti-Catholic sentiment at the time (catholics were a minority at that stage- yes, they overtook us protestants in the end!). http://www.historyaustralia.org.au/ifhaa/history/princealfred.htm
The one comforting fact you could take away from all this, is that it eventually DID end... we've got irish catholics in the parliament and a turncoat Englishman catholic at the helm of the nation.
At the time the Irish wanted to set up nation states of their own within the other states... they had about a snowflake's chance in hell.
There were also violent uprisings in Canada and the US, these were easily squashed by the official forces. The thing to remember, is that like then, the people who engage in radicalism and terrorism, 99% of the time are as dumb as a box of hammers.... the irish uprisings were the same, and like much of the home-grown terrorism we will see, although disturbing, is not a harbinger of the end of days. Things will get better with time. We'll stomp them out and it will eventually die.
