Kilmainham Gaol stood in silence as President Michael D Higgins laid a wreath to remember the leaders of the Rising.
Fourteen rebels, including Padraig Pearse, Joseph Plunkett and James Connolly, were executed in the Stone Breakers Yard a century ago.
As he placed a wreath at the spot where the men were shot by firing squad, Mr Higgins remembered "all those who died" during the events of 1916.
Three dozen guests including family members of the fallen heroes attended the solemn wreath-laying ceremony.
Defence Forces chaplain Fr Seamus Madigan urged the descendants to "keep the faith".
"In this place of final moments, we are intimately reminded of the comfort brought by faith to the leaders of the 1916 Rising," he said.
"On this Easter morning, we remember, reflect and re-imagine our belief in life after love and now, in their own final words of prayer, we recall the love and devotion of the executed leaders for family, for country and for God."
Hero Michael Mallin's granddaughter Una O'Callanain was among those who braved the chill to witness the tricolour being raised to full mast.
"My father was 12 when his father was executed," she recalled.
"It was very hard for him because he came to the gaol the night before his father was executed to say goodbye.
"My father never spoke to me about it at all until 1966 when he wrote a book about it, and that's when it began to all come out."
Praising the "dignified" commemoration, which was one of the many state ceremonial events taking place throughout the capital yesterday, Ms O'Callanain added: "Every time I come out here I become quite emotional because that's the place over there where they were shot.
"I try to visualise those prisoners who came out here 100 years ago. Their faith was so strong and they all went to their deaths with the knowledge that they could get to heaven.
"I'm very privileged to be here. It means an awful lot to me."
Twenty soldiers from the Army's 92nd Cadet Class stood to attention as Amhran na bhFiann echoed around the scene of the executions.
Kelly Smyth, from Ratoath, who is the only woman in the class, told of her pride at being in the guard of honour for the historic occasion.
"I'm from an Army family and the first to get into the cadetship," the 21-year-old told the Herald.
"In the build-up we were doing a lot of drills and 20 of us got picked, so it's a huge honour.
"A lot of excitement and a lot of nerves, but it's good to stand inside in the Stone Breakers Yard."
Earlier in the day, relatives had also gathered at Glasnevin Cemetery to commemorate those who paid the ultimate price for freedom.
Among those in attendance was Dualta O Broinn, the great-grandson of Peadar Kearney who wrote Amhran na bhFiann.