A new chapter of partnership and friendship has been opened between Ireland and Britain, the President has said.
The future can be changed and the state visit of Queen Elizabeth of Britain is the culmination of the success of the Northern Ireland peace process, Mary McAleese added.
She addressed a state dinner in Dublin attended by Elizabeth II, saying: "This evening we celebrate a new chapter in our relationship that may still be a work in progress, but happily has also become a work of progress, of partnership and friendship."
She said the past was a repository of bitterness but the future could be different.
"I am particularly proud of this island's peacemakers who having experienced first hand the appalling, toxic harvest of failing to resolve old hatreds and political differences, rejected the perennial culture of conflict and compromised enough to let a new future in."
She said she was proud of Ireland's difficult journey to national sovereignty and a republic which asserts religious and civil liberty.
"The collegial and co-operative relationship between the British and Irish Governments was crucial to the success of the peace process and we can thank the deepening engagement between us as equal partners in the European Union for the growth of friendship and trust," she added.
"The Governments' collaborative efforts to bring peace and power-sharing to Northern Ireland have yielded huge dividends for the peoples of these two islands."