It marks the start of the 2016 Centenary programme.
Jeremiah O'Donovan Rossa, a member of the Irish Republican Brotherhood, died in June 1915 and his funeral took place in Glasnevin Cemetery Dublin on 1st August that year.
The graveside oration was given by Pádraig Pearse and was seen as pivotal in the lead up to the 1916 Rising.
A volley of shots will be fired at this morning's commemoration.
Arts and Heritage Minister Heather Humphreys says the Centenary programme will be non-partisan and respectful
