Inez McCormack, one of the country's most respected trade unionists and the first female president of the Irish Congress of Trade Unions, has died after a long battle with cancer.
In a tribute, President Michael D Higgins said she was a passionate and committed human rights activist who fought all her life for the creation of a fairer society.
Born in Belfast in 1946, she studied social work at Trinity College Dublin and Queen's University Belfast, but devoted her working life to trade union activities.
She achieved significant policy improvements for the low-paid, and also campaigned for equality and human rights, especially for women.
Last month, during her visit to Belfast, US Secretary of State Hilary Clinton said: "Inez stands out amongst the extraordinary people I have worked with over the last 17 years. She inspired, motivated and challenged me often."
In the late 1960s she was prominently involved in Northern Ireland's Civil Rights Movement.
She also played an important behind-the-scenes role in the lead-up to the 1998 Good Friday Agreement.
In March 2010, the Oscar-winning actress Meryl Streep portrayed the character of Ms McCormack, in a Broadway production celebrating the work of seven women in different parts of the world.