The writer of a new drama set in 1880s Ulster says it warns "we can't afford to go back" to how things were before the Northern Irish peace process.
Death and Nightingales writer Allan Cubitt says there is a "deeply felt" divide that risked becoming "active" in the wake of the Brexit border row.
"Representing how divided things were back then is a reminder we can't let that divide reassert itself," he says.
Jamie Dornan and Matthew Rhys co-star in BBC Two's Death and Nightingales.
Set in County Fermanagh before the partition of Ireland, it tells of a young woman, played by newcomer Ann Skelly, who is torn between her Protestant stepfather and her Catholic lover.
The region's religious and territorial tensions serve as a backdrop to the three-part drama, which Cubitt adapted from Eugene McCabe's 1992 novel.
According to the writer, the action in McCabe's novel is set at "the start of modern terrorism... during the time of the Fenian dynamite campaign".
The campaign involved a series of bombings by Irish republicans that saw blasts at barracks, police stations and other targets in England and Scotland.
Sectarian violence continued after Ireland was divided in 1921, reaching its apogee during the period known as The Troubles.
Dornan, who was born in County Down in 1982 and grew up in the suburbs of Belfast, says he remembered that time all too well.
"You can't live and grow up in Northern Ireland in that time and not be affected by The Troubles," he tells reporters after a screening of Death and Nightingales.
"I have a very good understanding of it," he says of the divisions represented in the drama. "I could relate to it in my own way because I definitely experienced it."
Dornan, who previously worked with Cubitt on BBC drama The Fall, says he has "never felt I have any loyalty to either side" of the sectarian struggle.
"I was very lucky," he says. "I went to a school where there was a healthy mix of Catholic and Protestant, I could relate to both sides."
Filming in Northern Ireland this summer enabled the star of the Fifty Shades of Grey films a welcome chance to return to the place of his birth.
"I've been pretty crap about going home, so to have an excuse to be home for the summer was amazing, It was a joy."
"We had unbelievable heatwave weather," says Cubitt, who also directed the drama. "I kept wondering what it would be like when it was wet and grey."
Death and Nightingales begins on BBC Two on Wednesday at 21:00 GMT.