In Seamus De Burca's book about Peader Kearney "The Soldier's Song", the first two verses and chorus of "The Three-coloured Ribbon" are printed as Declan had it (except that it has "to set Ireland free"), with a dedication of the song "To Eva" (Kearney's wife); and it's subtitled as "Easter Week Ballad". There's no indication of when he wrote it, but I would think it's likely it would have ben while he was interned in Ballykinlar, after the Rising.