Mary Brennan Holahan was born in 1920 in Sexton Street, Abbeyside. She recalled that the family home was burned down along with others in the street in 1921 and that her family had a narrow escape from the fire. Her family later moved to Dublin where she was educated at the Loreto Convent, St. Stephen's Green. On leaving school she joined the Civil Service where she remained until her marriage. She was a member of the Republican Swimming Club in the 1930s. She had a lifelong interest in politics. She was branch secretary of the Save the German Children Society which brought German refugee children to Ireland in the 1940s. She was one of the many protesters who marched to save the Viking site at Wood Quay, Dublin in the 1970s.

When her children were reared Mary rekindled her interest in Art and sat extramural examinations in the History of European Painting at U.C.D and Trinity College for which she was twice awarded the Purser/Griffith scholarship. She also worked for the Institute of Public Administration and became administrator of the Irish branch of the Royal College of Practitioners. On retirement she began a degree course in the History of Art at Trinity. She graduated with honours in 1988 at the age of 68. She then worked as a research assistant to the author Bruce Arnold. In 1996 she published a biography of the artist Sarah Purser titled - 'A Portrait of Sarah Purser' which was the first work to concentrate on the history of the Purser family in Dungarvan. Mary also gave regular talks on Sarah Purser and the Irish Stained Glass movement. She died on 28 July 2001 and is survived by two sisters and her four children.