President Michael D Higgins commemorates centenary of first sitting of Dáil Éireann
The President of Ireland has said the world is witnessing the return of an "ugly xenophobic" corruption of nationalism.
Michael D Higgins also said that climate change is one of the greatest challenges facing Ireland.
Mr Higgins made the remarks during a keynote address to mark the centenary of the first sitting of Dáil Éireann.
Mr Higgins said: "Across the world, we are witnessing the return of an ugly, xenophobic corruption of nationalism, long since thought vanquished from our political life.
"The duty to welcome and shelter those fleeing war, persecution and famine - so often relied upon by Irish men and women throughout the ages - is now being openly disdained, even discarded, by elements in our European Union."
A special commemorative event was held on Monday at Dublin's Mansion House to coincide with the 100-year anniversary of the first public sitting - which took place on January 21, 1919.
Parliamentarians from both the lower and upper houses of the Irish parliament held a joint sitting in the round room of the Mansion House to commemorate the occasion.
TDs and senators, direct descendants of the members of the first Dáil, MLAs, ambassadors and representatives from parliaments across the EU were among the invited guests.
Mr Higgins warned attendees of the dangers of climate change.
He added: "In this century, our planet and our people face new dangers undreamed of by our forebears: the disastrous loss of natural habitats and species both here and across our shared and vulnerable planet, and the potentially catastrophic effects of climate change present the Ireland of today with stark challenges.
"Challenges that cannot wait to be addressed."
He also told those gathered that the establishment of Dáil Éireann was not only a revolutionary act of national self-determination, but "an act of defiance against an empire that ruled over vast territories and diverse peoples, an assertion that sovereignty belonged not to the crown, but to the Irish people alone".
"Given the great forces ranged against that claim, the first Dáil represented an act of extraordinary imagination and courage, a courage that would be called upon to be matched and surpassed by the Irish people time and time again in the turbulent and difficult years that followed," Mr Higgins said.
Mr Higgins added that it offered the people of Ireland hope.
"Our forebears were not merely opening a legislative assembly, they were founding a new nation, one capable of articulating and vindicating the rights and aspirations of the Irish people," he said.
Although there were only 27 elected members in attendance for the first session of the Dáil - some 34 others were in prison and some refused to take their seats - it marked a crucial step in the country's struggle for independence.
Members claimed the right of Ireland to self-government and adopted a provisional constitution.
The meeting took place within weeks of the 1918 elections, in which 69 Sinn Fein candidates were elected.
But the Sinn Féin elected representatives rejected the Westminster parliament and declared independence.
Mr Higgins told those gathered that those who had assembled in 1919 did so to realise a dream, but he said it must be remembered that the first Dáil did not represent the aspirations of all the people on the island.
"Many Irish citizens in Northern Ireland will join us today in celebrating the events of 100 years ago as a momentous step towards our independence," he said.
"Let us also acknowledge, however, that the legitimacy of Dáil Éireann and its institutions was not accepted by a significant number of people, particularly by a majority in the counties that were later to be incorporated into the entity that came to be Northern Ireland."
Mr Higgins added that it was important to reflect on both the successes and failures of the country's collective past.
In his speech, Taoiseach Leo Varadkar paid tribute to the country's forebearers but he acknowledged that some of the ideals outlined 100 years ago had not yet been fulfilled.
Mr Varadkar said: "Industrial schools, illegal adoptions, and mother and baby homes were a betrayal of those ideals.
"Although today the rate of child poverty in Ireland is only a fraction of what it was 100 years ago, and is falling, we must do better."
The inaugural meeting occurred on the same day as the outbreak of the Irish War of Independence.
The war raged for two years until 1921, after which 26 of the 32 counties on the island of Ireland became independent of the United Kingdom.
The Irish Free State was established in 1922 as a result of the Anglo-Irish Treaty.
Ireland went on to become a Republic in 1949.