She had never married, but since her arrival in the US in the 1920s, she'd seen a whole circle of her nieces and nephews follow her over from Ireland: by the end of her life, she was matriarch to a large family who believed they knew everything about their elderly aunt. Until Chris found the suitcase under her bed. In it were her Cumann na mBan membership papers and a detention order from 1923, signed by minister for defence Richard Mulcahy. It stated that Bridie Halpin was "a dangerous woman" and committed her to prison.

There are hundreds of stories like Bridie Halpin's and all have their roots within the fortress walls of Kilmainham Jail in Dublin. Between January and October 1923, in the white heat of the civil war, the ancient prison housed more than 500 women . . . all of them republicans fighting against the Free State forces. It was the only period in the jail's long history when it functioned exclusively as a women's prison, and it is also one of the most forgotten.

But the women of Kilmainham were determined to make their mark.

In the ancient, dank cells on 'A' wing, these women's names, politics and prison records remain. "Up the Republic! . . . Kathleen Walsh" is writ large across one wall. "Maggie Chamberlain, Kilmallock, arrested Tuesday night, March 20th 1923" is written in a small, neat hand on another. "Lie over Mick and make room for Dick and let Willie in between, " is carved into the plaster in another cell . . . a reference to Michael Collins, Mulcahy and William T Cosgrave which, says the jail's archivist Niamh O'Sullivan, either implies the three were political bedfellows, or more chillingly, refers to their graves. "One interpretation is that it is as a straightforward death threat. That's the civil war in your face."

It was an altogether gentler inscription that inspired artist Francis Duffy to paint Kilmainham's civil war women. In her cell, Nora O'Sullivan from Co Cork had written, "All I ask is remembrance; and if remembrance proves a task, forget." "That in itself was a challenge, " he says. "When I first went to Kilmainham, I didn't know about these women. A lot of them came out and were wiped off the history books. So when I heard that they were forgotten, I said I'm going to paint them. They deserve to be painted."

With the help of O'Sullivan, Duffy chose 14 of the 1923 women to paint.

Maud Gonne and Constance Markiewicz are among the portraits, but it is the more anonymous subjects that captured Duffy's imagination best. Bridie Halpin is among them . . .

according to O'Sullivan, her story is typical of many of the Kilmainham women. "They left here with a sense of failure. There were still these terrible splits in their families and their communities. Their republic was gone and they had to walk away from everything they'd dreamed of and hoped for."

Many of them died in their 20s and many more emigrated to the States.

Some, like Bridie Halpin, never spoke of their time in the jail. It is only now, after the women's deaths, that their families are learning their stories.

These days, O'Sullivan is inundated with requests . . . particularly from the US . . . for visits to the women's cells.

Because of the delicate nature of the crumbling plasterwork in the cells, these visits are by appointment only.

"All the adult children, sooner or later, they will all have come."

Katherine 'Jake' Folan's only daughter has been among the visitors to the prison where her mother was incarcerated when she was just 15. Her scribbles are everywhere . . . and outside the door of her cell, her final missive carries her name and the date of her release, 27 April, 1923.

A native of Galway, Jake was arrested for carrying messages to republicans in her pig-tails. But unlike many of the other Kilmainham women, says O'Sullivan, Jake had "the best time of her life" in the prison. "She blossomed here, bouncing around in the padded cell, missing out on school, which she hated." Still, she bore the scars of her incarceration: she was caught up in a clash between prisoners and wardens, and always maintained that the numerous miscarriages she suffered afterwards were a direct result of her injuries.

After a spell in Boston, she ultimately settled in the UK where she became a staunch royalist and a Conservative voter. At her own insistence, she returned to Galway at the end of her life and died there in 1989.

Jake, Bridie and a dozen of their fellow inmates are on show this weekend at the Art Ireland Exhibition at the RDS, but, says Duffy, his Civil War Women are very much a work in progress. "I ended up with 14 but I could probably do another 40."

He hopes to mount a bigger exhibition of an expanded series in the jail itself, where the forgotten women prisoners' names still stake their claim on the crumbling walls. "If somebody doesn't get credit for something they've done, then I bark about it, " says Duffy. "These women deserve their place."