Guest Stars Lydia McGuinness as Peggy Mahon Brian McCardie as James Connolly Steve Wall as Detective Coleman Jordanne Jones as Minnie Mahon Gus McDonagh as Monsignor Mulcahy Millie Donnelly as Gracie Mahon Jaelynne Wallace Ruane as Sadie Mahon Laurence O'Fuarain as Desmond Byrne Niamh Cusack as Nellie Cosgrave Barry Keoghan as Cormac McDevitt Marcus Lamb as Patrick Pearse Michael Feast as Sir Matthew Nathan Jason Cullen as Peter Mahon Ryan McAllister as Sylvester the Butler Joanne Brennan as Dr. Kathleen Lynn Lalor Roddy as Thomas Clarke Ruairí Heading as Fusilier McGarry Camille O'Sullivan as Countess Constance Marklevicz Kieran O'Reilly as Captain Robert Barton Sean Fox as Sean McDermott Jane Herbert as Greta the Maid Stefan Dunbar as Corporal Stewart Sebastian Thommen as Michael Collins Charlie Bonner as William Wylie Fred McCloskey as Sergeant McAuley Edwin Mullane as Brophy the debt collector James Craze as 'Blimey' O'Connor Mark Lambert as Brigadier Blackader Jed Murray as British Lieutenant Paul Booth as Captain Lee-Wilson Dan Siron as Liverpool Soldier