sentences:  Initially a pioneer of trade unionism, who fought to enshrine the principle of workers' representation against the opposition of the coal-owners, he was regarded in later life as a moderate voice believing that disputes should be solved through conciliation rather than industrial action.This drew him into conflict with younger and more militant leaders from the 1890s onwards.Although the defeat of the miners in the Welsh coal strike of 1898 was a clear defeat for Mabon's strategy, his prestige was sufficient to ensure that he became the first president of the South Wales Miners' Federation which was established in the wake of the dispute.