George Gilmore (1898-1985) fought in the Irish War of Independence and took the Anti-Treaty side during the Civil War. He came from northern Protestant background and was radical in his political outlook, being a committed leftwing Republican. He acted as secretary to Sean Lemass in the early 1920s before Fianna Fail was founded. Along with fellow radicals Peadar O'Donnell, Frank Ryan, Charlie Donnelly and Roddy Connolly he played a leading role in the foundation of the Republican Congress of 1934.

The Republican Congress was involved in a variety of political activity on issues such as workers’ rights and housing. Its approach managed to cross the sectarian divide, particularly in Belfast. One of its most significant achievements was to bring a contingent of Protestant workers from the Shankill Road to the annual Wolfe Tone Commemoration at Bodenstown in 1934.

George Gilmore supported progressive causes all his life, wrote articles and pamphlets in their defence and was widely regarded as a classical Protestant Republican in the Wolfe Tone tradition. In 1976 he delivered a paper on the Republican Congress to a public meeting organised by the Irish Sovereignty Movement. Fortunately this speech was recorded. On the audio tape he is introduced by Micheál O'Loingsigh, chairman of the Irish Sovereignty Movement. There is some interesting audience participation in the discussion on the paper.

More Information on Wikipedia and the following links:
Papers of George Gilmore
George Gilmore Obituary