A wreath is to be laid at Glasnevin Cemetery in Dublin today to mark the 90th anniversary of the death of O'Donovan Rossa.
The republican, who was born in 1831 at Rosscarbery, County Cork was imprisoned for his activities against the British government in Ireland and was then exiled to the United States.
Following his death in New York in 1915, his body was taken back to Ireland and buried in Glasnevin at a funeral attended by 10,000 mourners.
The graveside ceremony today is being organised by the Republican Commemoration Committee Dublin.
Marchers will assemble at Parnell Square at 2.30pm and begin walking to Glasnevin Cemetery.
After the laying of a wreath on the grave, there will be speeches, songs and a recitation of the famous graveside oration given by Padraig Pearse at O'Donovan Rossa's funeral.
"But the fools, the fools, the fools! They have left us our Fenian dead, and while Ireland holds these graves, Ireland unfree shall never be at peace," he said.
The committee said the main address would be given Sinn Fein member and ex-prisoner Martina Anderson.
"All are welcome regardless of party affiliation to honour one of Ireland's great patriots on this, the 90th anniversary of his funeral," said a spokesman.