President Michael D Higgins has paid tribute to former minister for education Niamh Bhreathnach, who has died aged 77.
Ms Bhreathnach was a Labour Party TD for Dún Laoghaire.
In a statement President Higgins said: "In her time in office she would go on to leave an extraordinary legacy of educational reform."
Her first appointment to Cabinet was in 1993 when she became Minister for Education, the first time that two women held Cabinet posts, with Máire Geoghegan-Quinn appointed Minister for Justice.
President Higgins said Ms Bhreatnach became education minister on the same day he was appointed Minister for Arts, Culture and the Gaeltacht, adding: "I can recall that we were all possessed of a great sense of anxiety that we must take our opportunity to get changes done and Niamh set about that task with gusto."
The President said that her "deep commitment to serving the public was given evidence by her returning to Dún Laghaire Rathdown Council and her continued work as an activist in the decades following her term as Minister.
"She remained deeply interested in the education sector and broader public affairs up to recent weeks. She will be deeply missed."
Among Ms Bhreathnach's achievements were the abolition of Third-Level undergraduate tuition fees, significant increases in education spending and a programme targeting schools in disadvantaged areas, both rural and urban - the forerunner of DEIS schools.
Labour Party leader Ivana Bacik said: "Niamh was a true feminist and socialist and an unstoppable campaigner for equality."
She added that Ms Bhreathnach made history by being appointed Minster for Education in her first day in the Dáil.
Tánaiste Micheál Martin said he was "deeply saddened" to learn of Ms Breathnach's passing.
In a statement, he described her as "dedicated and committed to education, particularly in the area of reform".
He said she was "always courteous and kind" and was "thoroughly committed to public service".
Speaking about her own time as minister, Ms Bhreathnach said: "The order in which I took decisions within the Department of Education was parent first, teacher second, minister third."
She is survived by her husband Tom Ferris and children Clíodhna and Macdara.