I suspect some went of their own volition, but I was curious if the leadership of the United Irishmen/IRB/IRA/and similar groups made a concerted appeal to Irish groups living outside of Ireland/rest of the UK to return and fight for the Irish Republican cause. Did they make a distinction between first generation Irish migrants or their descendants? Was there a particular time period or conflict where this recruiting more prevalent than not? Any info from any time period is welcome, but I'm mostly thinking in terms of major milestones such as the 1798 Rebellion, the Easter Rising, and the Troubles.