What led to the formation of the irish republican army?

Explanation: in 1916 the irish citizen army led a socialist uprising in dublin but lost 5 years later in 1921 the IRA was formed in 1922 they gained independence but had a civil war because of the treaty later in 1969 the IRA split in 2 the official ira which doesnt exist militarily but still exists in sinn fein and the provisional IRA or better known as the "provos" which fought in northern ireland to unite ireland there war on britian lasted from 1971 to 2005 while they technically lost they call themselves the undeafeted army because they were never deafeted and they were the ones who called peace

answer; obey the closest relative's wishes;