It came during the First World War, while leaders in Westminster were distracted by military matters in Europe, which were the focus of public opinion at the time.
The rebellion, an attempt to overthrow British rule in Ireland, began on 24 April 1916.
The relatives of those who fought in the Easter Rising also attended the annual mass and commemoration ceremony.
Meanwhile, Irish President Michael D Higgins, Taoiseach Enda Kenny and other ministers gathered at Arbour Hill for the state commemoration.
The Reclaim the Vision of 1916 group is hosting a parade – starting at 2pm at Merrion Square – which will make its way to the GPO, where a free open-air concert will take place from 3pm.
The GAA will also mark the centenary in Dublin’s Croke Park stadium this afternoon, with ‘Laocrhra, ‘ which has been billed as a “live event celebrating our national identity”.
The event takes place on 27 April at the Westville Country Club.
Recalling 1798 and the events that inspired the 1916 Irish rebellion, performers who took to the stage at Westport Town Hall include Brendan and Joanne Keegan, traditional singers Monica Brennan, Jackie Smalls and Charlie Keating, singer/songwriter Brian Duffy, and the legendary Frank McCaffrey, with readings performed by Tony McCabe and Peter Carney.
Sunday 24 April marks the actual 100th anniversary of the rising and thousands of people are expected at events around the country to mark the historical event.