Ireland is grieving for next-door neighbours as well as a neighbouring nation in the wake of the Smolensk air disaster, Archbishop of Dublin Diarmuid Martin told a special memorial mass.
Taoiseach Brian Cowen was among the dignitaries paying their respects to the 96 victims, including Polish President Lech Kaczynski, at the ceremony at St Audeon's Church in the capital.
Dr Martin said the sadness felt by Ireland was deepened because of the greater relations between the two nations in recent years through Polish immigration.
"Our grief is greater still here in Ireland because Poland and Polish people are an established part of our own family in this land," he said.
Mr Cowen, who gave the first reading from the Book of Lamentations, led a large congregation of Polish and Irish mourners including Lord Mayor of Dublin Emer Costello, Polish Ambassador to Ireland Tadeusz Szumowski, other public representatives and embassy staff.
Dr Martin said a generation of distinguished figures, who had worked to build a new democratic Europe-oriented Poland, had been "wiped away" in the atrocity.
The air disaster has opened a fresh wound in Polish history just as another was healing through its reconciliation with Russia on the anniversary of the Katyn massacre, he said.
The archbishop said Ireland's grief goes beyond what would be a natural human reaction to a tragedy.
President Mary McAleese is expected to travel to Krakow for the state funeral of President Kaczynski on Sunday, although there were concerns the volcanic ash cloud over parts of Europe could disrupt travel plans for some visiting dignitaries. Among world leaders who said they would go to the ceremony are US President Barack Obama, Russian President Dmitry Medvedev and German Chancellor Angela Merkel.
Poland is preparing a tradition-laden funeral for Mr Kaczynski and his wife, who were among the 96 people killed when their plane crashed on approach to Smolensk in Russia.