President Michael D Higgins addressed the annual commemoration of Michael Collins at Beal na mBlath in Co Cork, where the Irish revolutionary was killed in an ambush in 1922.
President Higgins became the first sitting Head of State to deliver the oration.
Mr Higgins said Mr Collins accepted that some form of partition was regarded as inevitable at the time for unionists "seeking a separate status in the north-east corner of the island".
"With the benefit of hindsight, it has become easier, perhaps, to appreciate the merits of the path of compromise which Michael Collins, however reluctantly and heavy-heartedly, chose to follow," he added.
"Few today would challenge the wisdom of his conscious decision 'not to coerce the North-East'.
"Yet, a century later historians differ as to the motivation of Michael Collins in relation to the assistance he sought to provide to forces in Northern Ireland in this period."
In Dublin, Social Protection Minister Leo Varadkar claimed that Britain's decision to leave the EU is being used to make a "land-grab" for Northern Ireland.
Good to attend the annual Collins/Griffith Commemoration. Visionary and reflective speech by @campaignforleo. pic.twitter.com/je02FjXq4x— Dale McDermott (@dalemcdermott) August 21, 2016
Minister Varadkar said he foresees a united Ireland in the future, but warned immediate moves by some in that direction after the Brexit result is counterproductive.
The reunification of the island of Ireland must be brought about through "respect and consent" and by accepting the identity of unionists and "finding a special place for them to thrive", he said.
Mr Varadkar was speaking at a commemoration of Michael Collins and Arthur Griffiths, key figures in the fight for Irish independence, at Glasnevin cemetery in Dublin.
"It was easy for some to jump on the Brexit result, and use it to make a land-grab for Northern Ireland," Mr Varadkar said.
"And it was counterproductive."
At glasnevin cemetery for Griffith Collins commemoration and speech by @campaignforleo pic.twitter.com/6CDpYf7XoF— Gary Healy (@GaryHealyIE) August 21, 2016
The shock Brexit result in June has sparked a renewed debate about a potential referendum on the Irish border.
A majority of voters in Northern Ireland want to remain as part of the European Union.
Citing Mr Griffiths's talks with Ulster unionists during the partition of Ireland, Mr Varadkar said his "inclusive vision" is the "only chance we have of securing lasting peace and achieving genuine unity on this island".
"I share the vision of An Taoiseach that foresees a united Ireland at some point in the future, and I share his belief in how it should be achieved," he added.
"Through respect and consent, by accepting the identity of the minority tradition and honouring their values by finding a special place for them to thrive, not through assimilation or the crude majoritarianism in a border poll."
Earlier in the summer, Taoiseach Enda Kenny suggested a border referendum could be closer after the UK's decision to leave the EU, but he later appeared to retreat from his position.
Last month, an opinion poll by Red C showed two out of three people in the Republic would vote for a united Ireland - a sharp rise in support for reunification since a similar opinion poll six years ago.
The comments came as Mr Varadkar also used his speech to urge his own Government to focus on building a social recovery as much as an economic recovery in the upcoming Budget.
Speaking as Fianna Fáail finance spokesperson Michael McGrath said his party wants to see all details of the budget before it is published amid a likely confrontational build-up to the financial document, Mr Varadkar said to ignore the need for social reforms would be to repeat the mistakes of "the boom years".
"Economic gains on their own, without a vision for society to accompany them, will result in a squandered prosperity that will ultimately be unsustainable. We had that during the boom years. We must ensure that we do not have it again in the recovery years," he said.
Additional reporting by Fiachra Ó Cionnaith.