Maureen Haughey's death, aged 91, ends a link to Irish history which dates back to the foundation of the State.
Mrs Haughey was married to Ireland's most controversial taoiseach, Charles Haughey, for over 50 years. She was the daughter of Seán Lemass, also a former taoiseach, a founder member of Fianna Fáil, and a veteran of the 1916 Easter Rising.
She was a very private person for all of her life, dedicating her time to being a home-maker and carer for her husband and four children. But in political circles she was known as a very dedicated defender of her husband, standing by him through all kinds of political and personal adversity.
Her uncle, Noel Lemass, was murdered in controversial circumstances in the aftermath of the Civil War of 1923 in an incident believed to have been caused by Free State agents. Her late brother, Noel Junior, also served as a Fianna Fáil TD and was a junior minister prior to his untimely death in 1976.
Unusually for her generation Maureen Lemass, the eldest of Seán Lemass's children, studied for a BComm degree at University College Dublin in the 1940s. Other contemporary students included Garret FitzGerald and his future wife, Joan.
It was here that she met her future husband, Cathal, who would soon become known universally as Charlie. They married when they were each aged 26 and in time they had four children - Conor, Ciarán, Eimear and Seán, who is a very popular TD for Dublin Bay North.
Mr Haughey became a Fianna Fáil TD in 1957 and held several ministerial posts. But in 1970 he was the focus of much controversy when he was sacked from government and charged with importing IRA arms.
In a remarkable career turnaround, he was elected Fianna Fáil leader and taoiseach in 1979, later serving two more times as taoiseach. But his life was replete with controversy even after his retirement in 1992 when some startling revelations about his finances made him the focus of prolonged tribunals of inquiry.
In 1999 the Haughey family was rocked by various revelations by 'Sunday Independent' social diarist, Terry Keane, the former wife of a High Court judge. Their relationship had been gossiped about for years previously.
Clearly the revelations caused much hurt and embarrassment in the Haughey family. But the couple remained together and Maureen continued to support an increasingly ailing Mr Haughey with his travails at the various tribunals of inquiry and parallel probes by the tax authorities.
On RTÉ'S 'Today With Seán O'Rourke' yesterday, the financial adviser, Des Peelo, said Mrs Haughey's support to her husband was vital at this time as he struggled to cope with the various inquiries.
Mr Peelo said he was not privy to many of the facts of the Terry Keane liaison - but he suggested that she had exaggerated many of the details. He said Mrs Haughey was "utterly unassuming" and had "a lovely presence".
"She had no airs and graces and was warm and intelligent. She was a very private individual, entirely without malice," Mr Peelo said, adding that he believed she had a strong influence on her husband, who died in 2006.
Seán Haughey announced his mother's death on Twitter. "So sad to announce that my mother passed away peacefully this morning - a truly remarkable woman. May she rest in peace," he posted.
The Fianna Fáil leader Micheál Martin expressed his party's deepest sympathies to the Haughey and Lemass families. "Maureen was a wonderfully warm, dignified and intelligent woman," Mr Martin said.
"She was a tower of strength to her late husband former taoiseach Charles Haughey and loving daughter of former taoiseach Seán Lemass. Throughout her distinguished life she witnessed some of the major turning points in Irish history."
Mr Martin described Mrs Haughey as a "very active woman" with a keen interest in the evolution of Irish society.
"She was a patriot who loved her country and retained a key interest in the development of Irish society. Her life was steeped in the cause of Irish republicanism and her family contributed significantly to its advancement," the Fianna Fáil leader said.
The Haughey family had lived at Abbeville, the 18th Century house in Kinsealy, near Malahide, Co Dublin, for almost 40 years. Mr Haughey had acquired Abbeville in 1969, at the age of 44, just after being re-appointed finance minister.
Mrs Haughey left the mansion in 2008.