The Ewart-Biggs literary prize has been awarded to Irish historian Tom Dunne for his study of the 1798 rising in Wexford.
It beat six other entries short-listed for the £5,000 sterling prize, which commemorates the British ambassador to Ireland who was assassinated in 1976.
Prof Dunne, professor emeritus of history at University College Cork, received his prize at a reception in Belfast this evening for his work " Rebellions: Memoir, Memory and 1798", published by Lilliput Press.
Speaking on behalf of the judges, Prof Roy Foster said there was a "powerful list of candidates" vying for the 2005 award.
"The choice was, as ever, a difficult one. But all the judges were struck by the combination of judiciousness, impartiality and intensity in Tom Dunne's book: a unique blend of memoir, cultural commentary and historical analysis," he said.
The seven short-listed entries were Peace in Irelandby Richard Bourke; Rebellionsby Tom Dunne; Armed Struggleby Richard English; The Transformation of Irelandby Diarmuid Ferriter; Himself Aloneby Dean Godson; David Trimbleby Frank Millar; and Swallowing the Sunby David Park.
The judges for the award were Professor Paul Arthur, Professor Roy Foster, Dr Maurice Hayes, Marigold Johnson, and Thomas Pakenham.
The award is presented to works that "embody the objectives of the prize, which are to promote and encourage peace and reconciliation in Ireland, a greater understanding between the peoples of Ireland, or closer co-operation between the partners of the European Community".
Mr Ewart-Biggs and a civil servant, Ms Judith Cook, died on July 21st, 1976, when an IRA bomb exploded under their car near the ambassador's residence in south Dublin.